水表面の和周波発生分光の実験と計算
山口祥一
Volume：10, Number：3, Mar. 2025, [Reviewed], [Invited], [Lead]
Scientific journal
A new rigid non-polarizable model for semi-heavy water: TIP4P/2005-SHWTetsuyuki Takayama; Takuhiro Otosu; Shoichi Yamaguchi
The Journal of Chemical Physics,
Volume：161,
Number：23, Dec. 2024,
[Reviewed]In molecular dynamics (MD) simulations of water, rigid non-polarizable models are still valuable and widely used because of their low computational cost and excellent performance. Most of such models have been for light water (H2O) for a long time, and a few have recently been reported for heavy water (D2O). The specific models of D2O are needed because of its notably slower dynamics and stronger hydrogen bond than H2O. To our knowledge, no models of semi-heavy water (HOD) were made, although HOD is the most abundant and, therefore, most important chemical species in isotopically diluted water (IDW) prepared by mixing equal amounts of H2O and D2O. For precise MD simulations of IDW, a specific model of HOD is definitely needed. Here, we report the development of a new rigid non-polarizable model of HOD, TIP4P/2005-SHW, on the basis of the most popular H2O model, TIP4P/2005, and its D2O counterpart, TIP4P/2005-HW. We show the details of the development and demonstrate the high reproducibility of TIP4P/2005-SHW in terms of the density, the temperature of maximum density, the viscosity, and the diffusion coefficient.
AIP Publishing, Scientific journal
DOI：https://doi.org/10.1063/5.0240271DOI ID：10.1063/5.0240271,
ISSN：0021-9606,
eISSN：1089-7690 Theoretical and experimental OD-stretch vibrational spectroscopy of heavy waterTetsuyuki Takayama; Takuhiro Otosu; Shoichi Yamaguchi
The Journal of Chemical Physics,
Volume：160,
Number：10, Apr. 2024,
[Reviewed]In view of the current situation in which the OD-stretch vibrational spectra have been scarcely computed with non-polarizable rigid D2O models, we investigate the IR and Raman spectra of D2O by using a newly-reported model TIP4P/2005-HW. From the comparison between the calculations and experimental data, we find the excellent performance of TIP4P/2005-HW for vibrational spectroscopy of D2O in the same manner as TIP4P/2005 for H2O, although one may still conveniently employ an alternative method that regards OH as putative OD to calculate the OD-stretch spectra with similar quality from TIP4P/2005 trajectories. We also demonstrate that the appropriate setting for the spectral simulation of D2O under the time-averaging approximation reflects the slower dynamics (i.e., slower motion of translation and rotation due to the heavier mass and stronger hydrogen bond) of D2O than H2O. Moreover, we show from the theoretical calculations that the established interpretation of the OH-stretch spectra of H2O is finely applicable to the OD-stretch of D2O.
AIP Publishing, Scientific journal
DOI：https://doi.org/10.1063/5.0200623DOI ID：10.1063/5.0200623,
ISSN：0021-9606,
eISSN：1089-7690 振動分光の実験と理論計算による結晶氷の分子構造研究
高山哲侑; 山口祥一
Volume：51, First page：1, Last page：10, Apr. 2024, [Invited]
Scientific journal
Complex phase of the nonresonant background in sum frequency generation spectroscopyKorenobu Matsuzaki; Shoichi Yamaguchi; Tahei Tahara
The Journal of Chemical Physics,
Volume：159,
Number：22, Dec. 2023
Sum frequency generation (SFG) spectroscopy is an interface-selective spectroscopic technique that enables us to selectively observe the vibrational or electronic resonances of molecules within a very thin interface layer. The interfacial properties probed by SFG are contained in a complex quantity called the second-order nonlinear susceptibility (χ2). It is usually believed that the imaginary part of χ2 (Im χ2) exhibits the resonant responses of the system, whereas the nonresonant responses appear solely in the real part of χ2 (Re χ2). However, it was recently theoretically pointed out that a portion of the nonresonant responses actually contributes to the observed Im χ2 spectra when the finite thickness of the interface layer is taken into account. In this study, by considering a simple air/liquid interface without any solutes as a model system, we theoretically evaluate the nonresonant contribution to experimentally accessible Im χ2 as well as to Re χ2, from which the complex phase of the nonresonant background is estimated. It is shown that the deviation of the complex phase from 0° or 180° is less than 1° even if the thickness of the interface layer is taken into account. This means that the nonresonant contribution to Im χ2 is practically negligible, and it is a very good approximation to think that the nonresonant background appears solely in Re χ2 in the case of air/liquid interfaces. This result implies that Im χ2 practically contains only the resonant responses of the system, and molecular resonances at the interface can be conveniently studied using Im χ2 spectra at such interfaces.
AIP Publishing, Scientific journal
DOI：https://doi.org/10.1063/5.0169712DOI ID：10.1063/5.0169712,
ISSN：0021-9606,
eISSN：1089-7690 Appraisal of TIP4P-type models at water surfaceShoichi Yamaguchi; Tetsuyuki Takayama; Takuhiro Otosu
The Journal of Chemical Physics,
Volume：159,
Number：17, Nov. 2023
In view of the current situation in which non-polarizable rigid water models have been scarcely examined against surface-specific properties, we appraise TIP4P-type models at the liquid water surface on the basis of heterodyne-detected sum frequency generation (HD-SFG) spectroscopy. We find in the HD-SFG spectrum of the water surface that the peak frequency of the hydrogen-bonded OH band, the half width at half maximum of the hydrogen-bonded OH band, and the full width at half maximum of the free OH band are best reproduced by TIP4P, TIP4P/Ew, and TIP4P/Ice, respectively, whereas it is already well known that TIP4P/2005 best reproduces the surface tension. These TIP4P-type models perform better at the water surface in terms of the present appraisal items than some polarizable models in the literature.
AIP Publishing, Scientific journal
DOI：https://doi.org/10.1063/5.0171999DOI ID：10.1063/5.0171999,
ISSN：0021-9606,
eISSN：1089-7690 Transferability of vibrational spectroscopic map from TIP4P to TIP4P-like water modelsTetsuyuki Takayama; Takuhiro Otosu; Shoichi Yamaguchi
The Journal of Chemical Physics,
Volume：158,
Number：13, Apr. 2023
We computed the IR, Raman, and sum frequency generation spectra of water in the OH-stretch region by employing the quantum/classical mixed approach that consists of a vibrational spectroscopic map and molecular dynamics (MD) simulation. We carried out the MD simulation with the TIP4P, TIP4P/2005, and TIP4P/Ice models and applied the map designed for TIP4P by Skinner et al. to each MD trajectory. Although the map is not tuned for TIP4P-like models, TIP4P/2005 and TIP4P/Ice provide the best reproduction of the experimental vibrational spectra of liquid water and crystalline ice, respectively. This result demonstrates the transferability of the map from TIP4P to TIP4P/2005 and TIP4P/Ice, meaning that one can choose an appropriate TIP4P-like model to calculate the vibrational spectra of an aqueous system without rebuilding the map.
AIP Publishing, Scientific journal
DOI：https://doi.org/10.1063/5.0146084DOI ID：10.1063/5.0146084,
ISSN：0021-9606,
eISSN：1089-7690 Experimental and Theoretical Heterodyne-Detected Sum Frequency Generation Spectroscopy of Isotopically Pure and Diluted Water Surfaces Shoichi Yamaguchi; Tetsuyuki Takayama; Yuki Goto; Takuhiro Otosu; Takuma Yagasaki
The Journal of Physical Chemistry Letters, Oct. 2022,
[Reviewed]Scientific journal
DOI：https://doi.org/10.1021/acs.jpclett.2c02533DOI ID：10.1021/acs.jpclett.2c02533,
ORCID：120487669 Experimental and Theoretical Raman Spectroscopy of Isotopically Pure and Diluted Ice VI Tetsuyuki Takayama; Kota Kishi; Takuhiro Otosu; Takuma Yagasaki; Shoichi Yamaguchi
The Journal of Physical Chemistry C, Oct. 2022,
[Reviewed]Scientific journal
DOI：https://doi.org/10.1021/acs.jpcc.2c05133DOI ID：10.1021/acs.jpcc.2c05133,
ORCID：120088265 DNA-Induced Reorganization of Water at Model Membrane Interfaces Investigated by Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy Prashant Chandra Singh; Mohammed Ahmed; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY B,
Volume：126,
Number：4,
First page：840,
Last page：846, Feb. 2022
Lipid-DNA complexes are important nonviral vectors to be used in gene therapy, which is one of the promising strategies for the cure of many diseases. Although interfacial water is expected to play a significant role in lipid-DNA complexation, a molecular-level understanding about the role of interfacial water in the DNA-lipid complexation is still sparse. In this study, the structure and orientation of water at cationic and zwitterionic lipid monolayer/water interfaces in the presence of DNA are studied by the use of interface-selective heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy. It is found that the adsorption of DNA at a cationic lipid interface drastically decreases the orientation of interfacial water reflecting the neutralization of the positively charged interface, whereas the adsorption of DNA at a zwitterionic lipid interface makes interfacial water become more "H-up", indicating that the originally zwitterionic interface becomes negatively charged due to the DNA adsorption. Furthermore, interfacial water having relatively strong hydrogen bonds is observed at both the cationic and zwitterionic lipid interfaces in the presence of DNA.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpcb.1c08581DOI ID：10.1021/acs.jpcb.1c08581,
ISSN：1520-6106,
eISSN：1520-5207,
Web of Science ID：WOS:000746682000001 Progress in phase-sensitive sum frequency generation spectroscopyShoichi Yamaguchi; Takuhiro Otosu
Physical Chemistry Chemical Physics,
Volume：23,
Number：34,
First page：18253,
Last page：18267, 2021
Representative methods of surface-selective phase-sensitive sum frequency generation spectroscopy are reviewed in terms of interferometer implementation for optical heterodyne detection.
Royal Society of Chemistry (RSC), Scientific journal
DOI：https://doi.org/10.1039/d1cp01994eDOI ID：10.1039/d1cp01994e,
ISSN：1463-9076,
eISSN：1463-9084 Resolving the Controversy over Dipole versus Quadrupole Mechanism of Bend Vibration of Water in Vibrational Sum Frequency Generation Spectra Mohammed Ahmed; Satoshi Nihonyanagi; Achintya Kundu; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY LETTERS,
Volume：11,
Number：21,
First page：9123,
Last page：9130, Nov. 2020
Recently, there has been controversy over whether the HOH bend signal of water in the vibrational sum frequency generation (VSFG) spectrum arises from the conventional dipole mechanism or the quadrupole mechanism. Here, we show that the Im chi((2)) (the imaginary part of the second-order nonlinear susceptibility) spectra of the HOH bend mode of water at oppositely charged monolayer/water interfaces all exhibit positive bands, irrespective of the difference in the sign of the charge at the interface. Furthermore, it is found that the peak frequency of the HOH bend band substantially changes depending on the chemical structure of the charged headgroup located at the interface. These results demonstrate that the VSFG signal of the HOH bend vibration is generated from interfacial water with the interfacial quadrupole mechanism that is associated with the large field gradient of incident lights localized in a very thin region at the interface.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpclett.0c02644DOI ID：10.1021/acs.jpclett.0c02644,
ISSN：1948-7185,
Web of Science ID：WOS:000589920000029 Structure of water and polymer at the buried polymer/water interface unveiled using heterodyne-detected vibrational sum frequency generation Anton Myalitsin; Sanat Ghosh; Shu-hei Urashima; Satoshi Nihonyanagi; Shoichi Yamaguchi; Takashi Aoki; Tahei Tahara
PHYSICAL CHEMISTRY CHEMICAL PHYSICS,
Volume：22,
Number：29,
First page：16527,
Last page：16531, Aug. 2020
The structure of the prototypical acrylic polymer (poly(methyl methacrylate): PMMA)/water interface is elucidated at the molecular level using heterodyne-detected sum-frequency generation. Two distinct OH groups of interfacial water are found at the interface: one forms hydrogen bonds with the carbonyl group and the other weakly interacts with the ester methyl group of the polymer surface.
ROYAL SOC CHEMISTRY, English, Scientific journal
DOI：https://doi.org/10.1039/d0cp02618bDOI ID：10.1039/d0cp02618b,
ISSN：1463-9076,
eISSN：1463-9084,
Web of Science ID：WOS:000556485900003 Hydrogen order at the surface of ice Ih revealed by vibrational spectroscopy
Yuki Nojima; Yuki Shioya; Hajime Torii; Shoichi Yamaguchi
Chem. Commun., Volume：56, Number：33, First page：4563, Last page：4566, Mar. 2020, [Reviewed]
English, Scientific journal
Effect of electrostatic interaction on the leaflet-specific diffusion in a supported lipid bilayer revealed by fluorescence lifetime correlation analysis Takuhiro Otosu; Shoichi Yamaguchi
PHYSICAL CHEMISTRY CHEMICAL PHYSICS,
Volume：22,
Number：3,
First page：1242,
Last page：1249, Jan. 2020
A supported lipid bilayer (SLB) is now an indispensable tool to analyze the dynamical properties of biomembranes. However, the effect of a solid support on the leaflet-specific lipid dynamics in a SLB remains elusive, which hampers the further application of the SLB as a model biomembrane. Here, we performed the leaflet-specific lipid diffusion analysis by means of two-dimensional fluorescence lifetime correlation spectroscopy to elucidate the effect of the electrostatic interaction between lipid headgroups and a glass surface on the lipid diffusion in each leaflet of the SLB. The results clearly showed the correlation between the strength of the electrostatic interaction and the lipid diffusion in the proximal leaflet of the SLB facing a glass surface. In particular, the electrostatic attraction between the cationic lipids and a negatively charged glass surface enhanced the lipid diffusion in the proximal leaflet of the SLB, providing important implications for the lipid dynamics not only in the SLB but also in biomembranes.
ROYAL SOC CHEMISTRY, English, Scientific journal
DOI：https://doi.org/10.1039/c9cp05833hDOI ID：10.1039/c9cp05833h,
ISSN：1463-9076,
eISSN：1463-9084,
Web of Science ID：WOS:000509371400030 Reduction of glass-surface charge density slows the lipid diffusion in the proximal leaflet of a supported lipid bilayer Takuhiro Otosu; Shoichi Yamaguchi
JOURNAL OF CHEMICAL PHYSICS,
Volume：151,
Number：2, Jul. 2019
Understanding the effect of a solid support on the dynamical properties of a supported lipid bilayer (SLB) is a prerequisite for the applications of SLB as a model biomembrane. Here, we applied two-dimensional fluorescence lifetime correlation spectroscopy to examine the effect of solution pH on the diffusion of lipids in the proximal/distal leaflets of a zwitterionic SLB. Leaflet-specific diffusion analyses at various pH revealed that the diffusion of lipids in the proximal leaflet facing a glass surface becomes slower by decreasing pH with the transition pH of similar to 7.4. We attributed it to the reduction of the surface charge density of a glass support. Furthermore, the data clearly showed that the lipid diffusion in the distal leaflet facing a bulk solution is insensitive to the change in the diffusion property of the proximal leaflet. This reflects a weak interleaflet coupling between the proximal and distal leaflets of the SLB. Published under license by AIP Publishing.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.5103221DOI ID：10.1063/1.5103221,
ISSN：0021-9606,
eISSN：1089-7690,
Web of Science ID：WOS:000486055700034 Perspective on sum frequency generation spectroscopy of ice surfaces and interfaces Shoichi Yamaguchi; Yudai Suzuki; Yuki Nojima; Takuhiro Otosu
CHEMICAL PHYSICS,
Volume：522,
First page：199,
Last page：210, Jun. 2019
This perspective is focused on surfaces and interfaces of crystalline ice studied with sum frequency generation (SFG) spectroscopy by several research groups within these twenty years. The intrinsic interface selectivity of SFG has already enabled one to determine structural aspects of the ice surfaces and interfaces through vibrational signatures of the OH stretch. Here we describe why SFG is suitable for ice surface science and how SFG has revealed the structure and dynamics of dangling bonds, quasi-liquid layer, hydrogen-bond network, and ordered protons at the ice surfaces, ice/substrate interfaces, and ice films on metal surfaces. In particular, we compare SFG spectra of ice reported by different groups to examine consistency between their experiments. We elaborate current controversies on a few SFG studies of ice before presenting future outlook for ice surface science by SFG. Additionally in the appendix we briefly explain some technical issues that may help us resolve conflicts and make progress in the right way.
ELSEVIER SCIENCE BV, English, Scientific journal
DOI：https://doi.org/10.1016/j.chemphys.2019.03.005DOI ID：10.1016/j.chemphys.2019.03.005,
ISSN：0301-0104,
eISSN：1873-4421,
Web of Science ID：WOS:000466713000027 Quantifying the Diffusion of Lipids in the Proximal/Distal Leaflets of a Supported Lipid Bilayer by Two-Dimensional Fluorescence Lifetime Correlation Spectroscopy Takuhiro Otosu; Shoichi Yamaguchi
JOURNAL OF PHYSICAL CHEMISTRY B,
Volume：122,
Number：45,
First page：10315,
Last page：10319, Nov. 2018
A supported lipid bilayer (SLB) is a versatile platform for examining the dynamical properties of biomembranes. However, the effect of a prerequisite solid substrate on the dynamics of a SLB remains very elusive. Especially, it is not clarified how the diffusivity of each leaflet in a SLB is affected by the SLB solid substrate interaction. In this study, we applied two-dimensional fluorescence lifetime correlation spectroscopy to a SLB for elucidating the diffusion of lipids in the proximal and distal leaflets of a SLB. We find that the autocorrelation curve of a fluorescent lipid in the proximal leaflet decays more slowly than that in the distal leaflet, meaning that the proximal leaflet is less diffusive. This result indicates stronger interaction between the proximal leaflet and a solid substrate.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpcb.8b08614DOI ID：10.1021/acs.jpcb.8b08614,
ISSN：1520-6106,
Web of Science ID：WOS:000451101100006 Total Internal Reflection Two-Dimensional Fluorescence Lifetime Correlation Spectroscopy Takuhiro Otosu; Shoichi Yamaguchi
Journal of Physical Chemistry B,
Volume：122,
Number：22,
First page：5758,
Last page：5764, Jun. 2018,
[Reviewed]Fluorescence lifetime correlation analysis is becoming a powerful tool to understand the conformational heterogeneity of biomolecules and their dynamics with an unprecedented detection sensitivity and time resolution. However, its application to the study of biomembranes is very limited. Here, we report on two-dimensional fluorescence lifetime correlation spectroscopy (2D FLCS) in combination with total internal reflection (TIR) microscopy (TIR 2D-FLCS). High depth resolution in TIR microscopy and species-specific correlation analysis in 2D FLCS give us the opportunity to selectively analyze molecules in or on a supported lipid bilayer, a model biomembrane formed on the glass surface. Feasibility experiments performed in this study clearly demonstrated that TIR 2D-FLCS has a potential to selectively analyze the diffusion and the conformational dynamics of proteins peripherally bound on the membrane in the presence of substantial amounts of unbound molecules in the bulk phase.
American Chemical Society, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpcb.8b01176DOI ID：10.1021/acs.jpcb.8b01176,
ISSN：1520-5207,
SCOPUS ID：85048247541 Local pH at the surface of hen egg white lysozyme Takuhiro Otosu; Kaito Kobayashi; Shoichi Yamaguchi
Chemical Physics Letters,
Volume：693,
First page：165,
Last page：169, Feb. 2018,
[Reviewed]The microenvironment at the surface of hen-egg-white lysozyme (HEWL) was examined by analyzing the change in pKa of fluorescein isothiocyanate (FITC) upon binding to the N-terminus of HEWL. The result showed that the local pH at the HEWL surface is higher than the bulk pH. Furthermore, the data showed that the difference between the local and bulk pH becomes larger with decreasing pH, suggesting HEWL repels more protons at lower pH. Because the local pH affects the protonation states of functional amino-acids at the protein surface, the results provide the fundamental insight into the microenvironment at the protein surface.
Elsevier B.V., English, Scientific journal
DOI：https://doi.org/10.1016/j.cplett.2018.01.026DOI ID：10.1016/j.cplett.2018.01.026,
ISSN：0009-2614,
SCOPUS ID：85040701289 Cooperative Hydrogen-Bond Dynamics at a Zwitterionic Lipid/Water Interface Revealed by 2D HD-VSFG Spectroscopy Ken-ichi Inoue; Prashant C. Singh; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY LETTERS,
Volume：8,
Number：20,
First page：5160,
Last page：5165, Oct. 2017,
[Reviewed]Molecular-level elucidation of hydration at biological membrane interfaces is of great importance for understanding biological processes. We studied ultrafast hydrogen-bond dynamics at a zwitterionic phosphatidylcholine/water interface by two-dimensional heterodyne-detected vibrational sum frequency generation (2D HD-VSFG) spectroscopy. The obtained 2D spectra confirm that the anionic phosphate and cationic choline sites are individually hydrated at the interface. Furthermore, the data show that the dynamics of water at the zwitterionic lipid interface is not a simple sum of the dynamics of the water species that hydrate to the separate phosphate and choline. The center line slope (CLS) analysis of the 2D spectra reveals that ultrafast hydrogen bond fluctuation is not significantly suppressed around the phosphate at the zwitterionic lipid interface, which makes the hydrogen-bond dynamics look similar to that of the bulk water. The present study indicates that the hydrogen-bond dynamics at membrane interfaces is not determined only by the hydrogen bond to a specific site of the interface but is largely dependent on the water dynamics in the vicinity and other nearby moieties, through the hydrogen-bond network.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpclett.7b02057DOI ID：10.1021/acs.jpclett.7b02057,
ISSN：1948-7185,
Web of Science ID：WOS:000413798300030 Proton Order toward the Surface of Ice I-h Revealed by Heterodyne-Detected Sum Frequency Generation Spectroscopy Yuki Nojima; Yudai Suzuki; Misato Takahashi; Shoichi Yamaguchi
JOURNAL OF PHYSICAL CHEMISTRY LETTERS,
Volume：8,
Number：20,
First page：5031,
Last page：5034, Oct. 2017,
[Reviewed]Using heterodyne-detected sum frequency generation (HD-SFG) spectroscopy, we investigated surface proton order at the basal, primary prism, and secondary prism faces of single-crystalline ice I-h at ca. 130 K. The complex phase of the obtained spectra clearly indicates that second-order nonlinear polarization from which the HD-SFG signal arises is generated exclusively at the surfaces. This suggests surface proton ordering along the normal, whereas the bulk remains proton-disordered, as is well known for ice I-h. A strong positive peak observed in the HD-SFG spectra enables us to determine the "direction" of the surface proton order as "H-up", that is, the hydrogen atom of the OH group pointing away from the bulk, irrespective of the ice faces. Reliable HD-SFG measurements carried out in the present study have greatly advanced our understanding of surface structure of ice I-h.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpclett.7b02198DOI ID：10.1021/acs.jpclett.7b02198,
ISSN：1948-7185,
ORCID：40809659,
Web of Science ID：WOS:000413798300010 Communication: Development of standing evanescent-wave fluorescence correlation spectroscopy and its application to the lateral diffusion of lipids in a supported lipid bilayer Takuhiro Otosu; Shoichi Yamaguchi
JOURNAL OF CHEMICAL PHYSICS,
Volume：147,
Number：4, Jul. 2017,
[Reviewed]We present standing evanescent-wave fluorescence correlation spectroscopy (SEW-FCS). This technique utilizes the interference of two evanescent waves which generates a standing evanescent-wave. Fringe-pattern illumination created by a standing evanescent-wave enables us to measure the diffusion coefficients of molecules with a super-resolution corresponding to one fringe width. Because the fringe width can be reliably estimated by a simple procedure, utilization of fringes is beneficial to quantitatively analyze the slow diffusion of molecules in a supported lipid bilayer (SLB), a model biomembrane formed on a solid substrate, with the timescale relevant for reliable FCS analysis. Furthermore, comparison of the data between SEW-FCS and conventional total-internal reflection FCS, which can also be performed by the SEW-FCS instrument, effectively eliminates the artifact due to afterpulsing of the photodiode detector. The versatility of SEW-FCS is demonstrated by its application to various SLBs. Published by AIP Publishing.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.4985871DOI ID：10.1063/1.4985871,
ISSN：0021-9606,
eISSN：1089-7690,
ORCID：36223899,
Web of Science ID：WOS:000406347200002 Heterodyne-detected sum frequency generation spectroscopy of aqueous interfaces
Yamaguchi Shoichi
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Volume：253, Apr. 2017, [Reviewed]
ISSN：0065-7727, Web of Science ID：WOS:000430569106683
Vibrational Coupling at the Topmost Surface of Water Revealed by Heterodyne-Detected Sum Frequency Generation Spectroscopy Yudai Suzuki; Yuki Nojima; Shoichi Yamaguchi
JOURNAL OF PHYSICAL CHEMISTRY LETTERS,
Volume：8,
Number：7,
First page：1396,
Last page：1401, Apr. 2017,
[Reviewed]Unraveling vibrational coupling is the key to consistently interpret vibrational spectra of complex molecular systems. The vibrational spectrum of the water surface heavily suffers from vibrational coupling, which hinders complete understanding of the molecular structure and dynamics of the water surface. Here we apply heterodyne detected sum frequency generation spectroscopy to the water surface and accomplish the assignment of a weak vibrational band located at the lower energy side of the free OH stretch. We find that this band is due to a combination mode of the hydrogen-bonded OH stretch and a low-frequency intermolecular vibration, and this combination band appears in the surface vibrational spectrum through anharmonic vibrational coupling that takes place exclusively at the topmost surface.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpclett.7b00312DOI ID：10.1021/acs.jpclett.7b00312,
ISSN：1948-7185,
ORCID：36223900,
Web of Science ID：WOS:000398884800012 Weakly Hydrogen-Bonded Water Inside Charged Lipid Monolayer Observed with Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy Yuki Nojima; Yudai Suzuki; Shoichi Yamaguchi
JOURNAL OF PHYSICAL CHEMISTRY C,
Volume：121,
Number：4,
First page：2173,
Last page：2180, Feb. 2017,
[Reviewed]Many biological processes such as photosynthesis and signal transduction proceed at lipid/water interfaces. Although water molecules inside lipid membranes are considered to have a critical role in these processes, it has been difficult to experimentally observe those water molecules with high selectivity. Here, we measure the Im chi((2)) (imaginary part of second-order nonlinear optical susceptibility) spectra of water at anionic lipid (1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol, DPPG) and cationic lipid (1,2-dipalmitoyl-3trimethylammonium-propane, DPTAP) interfaces with single-channel heterodyne-detected sum frequency generation spectroscopy and investigate the structure of water molecules at the lipid interfaces. The presence of weakly hydrogen-bonded water molecules located above the lipid head group is clearly identified. The Im chi((2)) spectra indicate that water molecules above the head group are oriented oppositely to those below the head group and they donate hydrogen bonds to the carbonyl and glycerol groups of the lipids. It is likely that water molecules inside the lipid monolayers can freely flip without terminating the weak hydrogen bonds.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpcc.6b09229DOI ID：10.1021/acs.jpcc.6b09229,
ISSN：1932-7447,
ORCID：31195802,
Web of Science ID：WOS:000393443200017 Comment on "Phase reference in phase-sensitive sum-frequency vibrational spectroscopy" [J. Chem. Phys. 144, 244711 (2016)] Shoichi Yamaguchi
JOURNAL OF CHEMICAL PHYSICS,
Volume：145,
Number：16, Oct. 2016,
[Reviewed]AMER INST PHYSICS, English
DOI：https://doi.org/10.1063/1.4965437DOI ID：10.1063/1.4965437,
ISSN：0021-9606,
eISSN：1089-7690,
ORCID：29445417,
Web of Science ID：WOS:000387586200058 Femtosecond Hydrogen Bond Dynamics of Bulk-like and Bound Water at Positively and Negatively Charged Lipid Interfaces Revealed by 2D HD-VSFG Spectroscopy Prashant Chandra Singh; Ken-ichi Inoue; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION,
Volume：55,
Number：36,
First page：10621,
Last page：10625, Aug. 2016,
[Reviewed]Interfacial water in the vicinity of lipids plays an important role in many biological processes, such as drug delivery, ion transportation, and lipid fusion. Hence, molecular-level elucidation of the properties of water at lipid interfaces is of the utmost importance. We report the two-dimensional heterodyne-detected vibrational sum frequency generation (2D HD-VSFG) study of the OH stretch of HOD at charged lipid interfaces, which shows that the hydrogen bond dynamics of interfacial water differ drastically, depending on the lipids. The data indicate that the spectral diffusion of the OH stretch at a positively charged lipid interface is dominated by the ultrafast (<approximate to 100fs) component, followed by the minor sub-picosecond slow dynamics, while the dynamics at a negatively charged lipid interface exhibit sub-picosecond dynamics almost exclusively, implying that fast hydrogen bond fluctuation is prohibited. These results reveal that the ultrafast hydrogen bond dynamics at the positively charged lipid-water interface are attributable to the bulk-like property of interfacial water, whereas the slow dynamics at the negatively charged lipid interface are due to bound water, which is hydrogen-bonded to the hydrophilic head group.
WILEY-V C H VERLAG GMBH, English, Scientific journal
DOI：https://doi.org/10.1002/anie.201603676DOI ID：10.1002/anie.201603676,
ISSN：1433-7851,
eISSN：1521-3773,
ORCID：29445418,
Web of Science ID：WOS:000383473600014 Bend Vibration of Surface Water Investigated by Heterodyne-Detected Sum Frequency Generation and Theoretical Study: Dominant Role of Quadrupole Achintya Kundu; Shogo Tanaka; Tatsuya Ishiyama; Mohammed Ahmed; Ken-ichi Inoue; Satoshi Nihonyanagi; Hiromi Sawai; Shoichi Yamaguchi; Akihiro Morita; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY LETTERS,
Volume：7,
Number：13,
First page：2597,
Last page：2601, Jul. 2016,
[Reviewed]Heterodyne-detected vibrational sum frequency generation spectroscopy was applied to the water surface for measuring the imaginary part of second-order nonlinear susceptibility (Im chi((2))) spectrum in the bend frequency region for the first time. The observed Im chi((2)) spectrum shows an overall positive band around 1650 cm(-1), contradicting former theoretical predictions. We further found that the Im chi((2))) spectrum of NaI aqueous solution exhibits an even larger positive band, which is apparently contrary to the flip-flop orientation of surface water. These unexpected observations are elucidated by calculating quadrupole contributions beyond the conventional dipole approximation. It is indicated that the Im chi((2)) spectrum in the bend region has a large quadrupole contribution from the bulk water.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpclett.6b00657DOI ID：10.1021/acs.jpclett.6b00657,
ISSN：1948-7185,
ORCID：28499888,
Web of Science ID：WOS:000379457400052 Partially Hydrated Electrons at the Air/Water Interface Observed by UV-Excited Time-Resolved Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy Korenobu Matsuzaki; Ryoji Kusaka; Satoshi Nihonyanagi; Shoichi Yamaguchi; Takashi Nagata; Tahei Tahara
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,
Volume：138,
Number：24,
First page：7551,
Last page：7557, Jun. 2016,
[Reviewed]Hydrated electrons are the most fundamental anion species, consisting only of electrons and surrounding water molecules. Although hydrated electrons have been extensively studied in the bulk aqueous solutions, even their existence is still controversial at the water surface. Here, we report the observation and characterization of hydrated electrons at the air/water interface using new time-resolved interface-selective nonlinear vibrational spectroscopy. With the generation of electrons at the air/water interface by ultraviolet photoirradiation, we observed the appearance of a strong transient band in the OH stretch region by heterodyne-detected vibrational sum-frequency generation. Through the comparison with the time-resolved spectra at the air/indole solution interface, the transient band was assigned to the vibration of water molecules that solvate electrons at the interface. The analysis of the frequency and decay of the observed transient band indicated that the electrons are only partially hydrated at the water surface, and that they escape into the bulk within 100 ps.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jacs.6b02171DOI ID：10.1021/jacs.6b02171,
ISSN：0002-7863,
ORCID：28499890,
Web of Science ID：WOS:000378584600026 Water Structure at the Buried Silica/Aqueous Interface Studied by Heterodyne-Detected Vibrational Sum-Frequency Generation Anton Myalitsin; Shu-hei Urashirna; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY C,
Volume：120,
Number：17,
First page：9357,
Last page：9363, May 2016,
[Reviewed]Complex chi((2)) spectra of buried silica/isotopically diluted water (HOD-D2O) interfaces were measured using multiplex heterodyne-detected vibrational sum frequency generation spectroscopy to elucidate the hydrogen bond structure and up/down orientation of water at the silica/water interface at different pHs. The data show that-vibrational coupling (inter- and/or intrarnolecular coupling) plays a significant role in determining the chi((2)) spectral feature of silica/H2O interfaces and indicate that the doublet feature in the H2O spectra does not represent two distinct water structures (i.e., the ice and liquid-like structures) at the silica/water interface. The observed pH dependence of the imaginary chi((2)) spectra is explained by (1) H-up oriented water donating a hydrogen bond to the oxygen atom of silanolate, which is accompanied by H-up water oriented by the electric field created by the negative charge of silanolate, (2) H-up oriented water which donates a hydrogen bond to the neutral silanol oxygen, and (3) H-down oriented water which accepts hydrogen bonds from the neutral silanol and donates hydrogen bonds to bulk water molecules. The broad continuum of the OH stretch band of HOD-D2O and a long tail in the low frequency region represent a wide distribution of strong hydrogen bonds at the silica/water interface, particularly at the low pH.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpcc.6b03275DOI ID：10.1021/acs.jpcc.6b03275,
ISSN：1932-7447,
ORCID：28499891,
Web of Science ID：WOS:000375631100042 Efficient Spectral Diffusion at the Air/Water Interface Revealed by Femtosecond Time-Resolved Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy Ken-ichi Inoue; Tatsuya Ishiyama; Satoshi Nihonyanagi; Shoichi Yamaguchi; Akihiro Morita; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY LETTERS,
Volume：7,
Number：10,
First page：1811,
Last page：1815, May 2016,
[Reviewed]Femtosecond vibrational dynamics at the air/water interface is investigated by time-resolved heterodyne-detected vibrational sum frequency generation (TR-HD-VSFG) spectroscopy and molecular dynamics (MD) simulation. The low- and high-frequency sides of the hydrogen-bonded (HB) OH stretch band at the interface are selectively excited with special attention to the bandwidth and energy of the pump pulses. Narrow bleach is observed immediately after excitation of the high-frequency side of the HB OH band at similar to 3500 cm(-1), compared to the broad bleach observed with excitation of the low-frequency side at similar to 3300 cm(-1). However, the time-resolved spectra observed with the two different excitations become very similar at 0.5 ps and almost indistinguishable by 1.0 ps. This reveals that efficient spectral diffusion occurs regardless of the difference of the pump frequency. The experimental observations are well-reproduced by complementary MD simulation. There is no experimental and theoretical evidence that supports extraordinary slow dynamics in the high-frequency side of the FIB OH band, which was reported before.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpclett.6b00701DOI ID：10.1021/acs.jpclett.6b00701,
ISSN：1948-7185,
ORCID：28499889,
Web of Science ID：WOS:000376421200010 Accurate determination of complex chi((2)) spectrum of the air/water interface Satoshi Nihonyanagi; Ryoji Kusaka; Ken-ichi Inoue; Aniruddha Adhikari; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：143,
Number：12, Sep. 2015,
[Reviewed]Discussion on the structure of the water surface relies on accurate determination of the chi((2)) spectrum. For obtaining accurate chi((2)) spectrum of the air/water interface in the OH stretch region, we performed heterodyne-detected vibrational sum-frequency generation measurements with a high phase accuracy, and also examined the validity of the phase and amplitude calibration using different non-resonant materials. In contrast to the previous reports, it was concluded that the imaginary part of the chi((2)) spectrum of the air/water interface does not exhibit noticeable positive resonance in the low frequency region within the experimental error. This result urges us to reconsider the structure of the air/water interface based on the accurate chi((2)) spectrum. (C) 2015 AIP Publishing LLC.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.4931485DOI ID：10.1063/1.4931485,
ISSN：0021-9606,
eISSN：1089-7690,
ORCID：28499893,
Web of Science ID：WOS:000362568100045 Development of single-channel heterodyne-detected sum frequency generation spectroscopy and its application to the water/vapor interface Shoichi Yamaguchi
JOURNAL OF CHEMICAL PHYSICS,
Volume：143,
Number：3, Jul. 2015,
[Reviewed]Single-channel heterodyne-detected sum frequency generation (HD-SFG) spectroscopy for selectively measuring vibrational spectra of liquid interfaces is presented. This new methodology is based on optical interference between sum frequency signal light from a sample interface and phase-controlled local oscillator light. In single-channel HD-SFG, interferometric and spectrometric measurements are simultaneously carried out with an input IR laser scanned in a certain wavenumber range, which results in a less task than existing phase-sensitive sum frequency spectroscopy. The real and imaginary parts of second-order nonlinear optical susceptibility (chi((2))) of interfaces are separately obtained with spectral resolution as high as 4 cm(-1) that is approximately six times better than existing multiplex HD-SFG. In this paper, the experimental procedure and theoretical background of single-channel HD-SFG are explicated, and its application to the water/vapor interface is demonstrated, putting emphasis on the importance of a standard for the complex phase of chi((2)). (C) 2015 AIP Publishing LLC.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.4927067DOI ID：10.1063/1.4927067,
ISSN：0021-9606,
eISSN：1089-7690,
ORCID：28499896,
Web of Science ID：WOS:000358429800013 Development of Electronic Sum Frequency Generation Spectroscopies and Their Application to Liquid Interfaces Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY C,
Volume：119,
Number：27,
First page：14815,
Last page：14828, Jul. 2015,
[Reviewed]This feature article describes our recent work on the development of interface-selective second-order nonlinear electronic spectroscopies and their application to molecular structure and dynamics at liquid interfaces. We describe three methods that measure electronically resonant second-order nonlinear optical susceptibility (chi((2))) of interfacial molecules without contribution from the bulk: electronic sum-frequency generation (ESFG) provides high-quality interfacial electronic spectra by employing the combination of narrow-band and broad-band visible/near-infrared femtosecond pulses. Time-resolved ESFG (TR-ESFG) is the extension of ESFG to time-resolved measurements and provides femtosecond time-resolved electronic spectra at interfaces. Heterodyne-detected ESFG (HD-ESFG) is the ultimate second-order nonlinear electronic spectroscopy that directly provides the real and imaginary parts of chi((2)). In particular, the imaginary chi((2)) spectra obtained with HD-ESFG can be directly compared to the absorption spectra of bulk solution, and their signs contain information about the absolute orientation of the interfacial molecules. These interface-selective electronic spectroscopies enable rigorous comparison between the electronic spectra of liquid interfaces and those of bulk liquids, and the application to the following topic is discussed in this article: effective polarity at the air/water interface, interfacial ultrafast dynamics, absolute alignment of interfacial molecules, pH of the air/water interface, and the origin of nonresonant background. These studies reveal unique properties of molecules at air/liquid interfaces, which is markedly different from that in the bulk from a microscopic viewpoint.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/acs.jpcc.5b02375DOI ID：10.1021/acs.jpcc.5b02375,
ISSN：1932-7447,
ORCID：28499895,
Web of Science ID：WOS:000357964900001 2D heterodyne-detected sum frequency generation study on the ultrafast vibrational dynamics of H2O and HOD water at charged interfaces Ken-ichi Inoue; Satoshi Nihonyanagi; Prashant C. Singh; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：142,
Number：21, Jun. 2015,
[Reviewed]Two-dimensional heterodyne-detected vibrational sum-frequency generation (2D HD-VSFG) spectroscopy is applied to study the ultrafast vibrational dynamics of water at positively charged aqueous interfaces, and 2D HD-VSFG spectra of cetyltrimethylammonium bromide (CTAB)/water interfaces in the whole hydrogen-bonded OH stretch region (3000 cm(-1) <= omega(pump) <= 3600 cm(-1)) are measured. 2D HD-VSFG spectrum of the CTAB/isotopically diluted water (HOD-D2O) interface exhibits a diagonally elongated bleaching lobe immediately after excitation, which becomes round with a time constant of similar to 0.3 ps due to spectral diffusion. In contrast, 2D HD-VSFG spectrum of the CTAB/H2O interface at 0.0 ps clearly shows two diagonal peaks and their cross peaks in the bleaching region, corresponding to the double peaks observed at 3230 cm(-1) and 3420 cm(-1) in the steady-state HD-VSFG spectrum. Horizontal slices of the 2D spectrum show that the relative intensity of the two peaks of the bleaching at the CTAB/H2O interface gradually change with the change of the pump frequency. We simulate the pump-frequency dependence of the bleaching feature using a model that takes account of the Fermi resonance and inhomogeneity of the OH stretch vibration, and the simulated spectra reproduce the essential features of the 2D HD-VSFG spectra of the CTAB/H2O interface. The present study demonstrates that heterodyne detection of the time-resolved VSFG is critically important for studying the ultrafast dynamics of water interfaces and for unveiling the underlying mechanism. (C) 2015 AIP Publishing LLC.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.4918644DOI ID：10.1063/1.4918644,
ISSN：0021-9606,
eISSN：1089-7690,
ORCID：28499892,
Web of Science ID：WOS:000355931800035 Anomalous effective polarity of an air/liquid-mixture interface: a heterodyne-detected electronic and vibrational sum frequency generation study Sudip Kumar Mondal; Ken-ichi Inoue; Shoichi Yamaguchi; Tahei Tahara
PHYSICAL CHEMISTRY CHEMICAL PHYSICS,
Volume：17,
Number：37,
First page：23720,
Last page：23723, 2015,
[Reviewed]We study the effective polarity of an air/liquid-mixture interface by using interface-selective heterodyne-detected electronic sum frequency generation (HD-ESFG) and vibrational sum frequency generation (HD-VSFG) spectroscopies. With water and N,N-dimethyl-formamide (DMF) chosen as two components of the liquid mixture, the bulk polarity of the mixture is controlled nearly arbitrarily by the mixing ratio. The effective polarity of the air/mixture interface is evaluated by HD-ESFG with a surface-active solvatochromic molecule used as a polarity indicator. Surprisingly, the interfacial effective polarity of the air/mixture interface increases significantly, when the bulk polarity of the mixture decreases (i.e. when the fraction of DMF increases). Judging from the hydrogen-bond structure at the air/mixture interface clarified by HD-VSFG, this anomalous change of the interfacial effective polarity is attributed to the interface-specific solvation structure around the indicator molecule at the air/mixture interface.
ROYAL SOC CHEMISTRY, English, Scientific journal
DOI：https://doi.org/10.1039/c5cp04264jDOI ID：10.1039/c5cp04264j,
ISSN：1463-9076,
eISSN：1463-9084,
ORCID：28499894,
Web of Science ID：WOS:000361543200004 Interfacial water in the vicinity of a positively charged interface studied by steady-state and time-resolved heterodyne-detected vibrational sum frequency generation Prashant Chandra Singh; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：141,
Number：18, Nov. 2014,
[Reviewed]To investigate the properties of water in the close vicinity of a positively charged surfactant/water interface, steady-state and femtosecond time-resolved interfacial vibrational spectra were measured in the presence of excess alkali halide salts. The steady-state Im chi((2)) spectra show a drastic intensity decrease with excess salts, indicating that the thickness of the probed water layer is substantially reduced. Fluoride salts do not noticeably affect spectral features in the OH stretch region whereas the chloride and bromide salts induce significant blue shifts of the OH stretch frequency. Femtosecond time-resolved Delta Im chi((2)) spectra obtained with fluoride salts exhibit a very broad bleach even at 0 fs as observed without excess salts, while chloride and bromide salts give rise to a narrow spectral hole burning. These results indicate that the excess chloride and bromide ions strongly interact with interfacial water in the vicinity of the charged interface and it suppresses intramolecular coupling (i.e., Fermi resonance) that causes spectral broadening. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.4897265DOI ID：10.1063/1.4897265,
ISSN：0021-9606,
eISSN：1089-7690,
ORCID：28499899,
Web of Science ID：WOS:000344847600071 Counterion Effect on Interfacial Water at Charged Interfaces and Its Relevance to the Hofmeister Series Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,
Volume：136,
Number：17,
First page：6155,
Last page：6158, Apr. 2014,
[Reviewed]Specific counterion effects represented by Hofmeister series are important for a variety of phenomena such as protein precipitations, surface tensions of electrolytes solutions, phase transitions of surfactants, etc. We applied heterodyne-detected vibrational sum-frequency generation spectroscopy to study the counterion effect on the interfacial water at charged interfaces and discussed the observed effect with relevance to the Hofmeister series. Experiments were carried out for model systems of positively charged cetyltrimethylammonium monolayer/electrolyte solution interface and negatively charged dodecylsulfate monolayer/electrolyte interface. At the positively charged interface, the intensity of the OH band of the interfacial water decreases in the order of the Hofmeister series, suggesting that the adsorbability of halide anions onto the interface determines the Hofmeister order as previously proposed by Zhang and Cremer (Curr. Opin. Chem. Biol. 2006, 10, 658-663). At the negatively charged interfaces, on the other hand, the OH band intensity does not depend significantly on the countercation, whereas variation in the hydrogen-bond strength of the interfacial water is well correlated with the Hofmeister order of the cation effect. These results provide new insights into the molecular level mechanisms of anionic and cationic Hofmeister effects.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/ja412952yDOI ID：10.1021/ja412952y,
ISSN：0002-7863,
ORCID：28499897,
Web of Science ID：WOS:000335369200002 Evaluation of pH at Charged Lipid/Water Interfaces by Heterodyne-Detected Electronic Sum Frequency Generation Achintya Kundu; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY LETTERS,
Volume：5,
Number：4,
First page：762,
Last page：766, Feb. 2014,
[Reviewed]Although the interface pH at a biological membrane is important for biological processes at the membrane, there has been no systematic study to evaluate it. We apply novel interface-selective nonlinear spectroscopy to the evaluation of the pH at model biological membranes (lipid/water interfaces). It is clearly shown that the pH at the charged lipid/water interfaces is substantially deviated from the bulk pH. The pH at the lipid/water interface is higher than that in the bulk when the head group of the lipid is positively charged, whereas the pH at the lipid/water interface is lower when the lipid has a negatively charged head group.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jz500107eDOI ID：10.1021/jz500107e,
ISSN：1948-7185,
ORCID：28499898,
Web of Science ID：WOS:000331860900021 Ultrafast vibrational dynamics of water at a zwitterionic lipid/water interface revealed by two-dimensional heterodyne-detected vibrational sum frequency generation (2D HD-VSFG) Ken-Ichi Inoue; Prashant Chandra Singh; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
Optics InfoBase Conference Papers, 2014
2D HD-VSFG is applied to the study of ultrafast vibrational dynamics at a zwitterionic lipid/water interface for the first time. The 2D spectrum reveals spectral diffusion of three distinct water species existing at the interface. Ultrafast Phenomena 2014 © 2014 OSA.
Optical Society of America (OSA), English, International conference proceedings
DOI：https://doi.org/10.1364/up.2014.07.mon.p1.27DOI ID：10.1364/up.2014.07.mon.p1.27,
ISSN：2162-2701,
SCOPUS ID：85087192595 Communication: Ultrafast vibrational dynamics of hydrogen bond network terminated at the air/water interface: A two-dimensional heterodyne-detected vibrational sum frequency generation study Prashant Chandra Singh; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：139,
Number：16, Oct. 2013,
[Reviewed]Ultrafast vibrational dynamics of hydrogen bond network at the air/water interface is revealed by two-dimensional heterodyne-detected vibrational sum frequency generation (2D HD-VSFG) spectroscopy. Three diagonal peaks are clearly observed in the 2D HD-VSFG spectrum, which correspond to the negative and positive hydrogen-bonded OH stretch bands and the positive "free" OH stretch band in the steady-state HD-VSFG spectrum. A diagonally elongated bleaching lobe of the hydrogen-bonded OH at 0 ps indicates that it is partly inhomogeneously broadened. This diagonal elongation vanishes in a few hundred femtoseconds, implying the ultrafast spectral diffusion in the hydrogen-bonded OH band. Off-diagonal cross peaks between each OH oscillator are clearly observed instantaneously within the time resolution of 0.2 ps, suggesting that they are vibrationally coupled through anharmonicity and/or energy transfer. (C) 2013 AIP Publishing LLC.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.4826095DOI ID：10.1063/1.4826095,
ISSN：0021-9606,
eISSN：1089-7690,
ORCID：28499901,
Web of Science ID：WOS:000326637500001 Vibrational Sum Frequency Generation by the Quadrupolar Mechanism at the Nonpolar Benzene/Air Interface Korenobu Matsuzaki; Satoshi Nihonyanagi; Shoichi Yamaguchi; Takashi Nagata; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY LETTERS,
Volume：4,
Number：10,
First page：1654,
Last page：1658, May 2013,
[Reviewed]The interface selectivity of vibrational sum frequency generation (VSFG) spectroscopy is explained under the dipole approximation as resulting from the breakdown of inversion symmetry at the interface. From this viewpoint, VSFG is not expected to occur at the interface consisting of centrosymmetric molecules, because the inversion symmetry is preserved even at the interface. In reality, however, VSFG at the nonpolar benzene/air interface has been observed with traditional homodyne-detected VSFG. Here we report a heterodyne-detected VSFG study of the benzene/air interface. The result strongly indicates that VSFG at this interface cannot be explained within the framework of the dipole approximation. The selection rule and polarization dependence of the observed VSFG signal show that the quadrupole transition plays an essential role because of the field discontinuity at the interface. This finding implies the applicability of interface-selective VSFG to the nonpolar interfaces comprising centrosymmetric molecules, which opens a new possibility of VSFG spectroscopy.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jz400829kDOI ID：10.1021/jz400829k,
ISSN：1948-7185,
ORCID：28499905,
Web of Science ID：WOS:000321793800013 Agreement between Experimentally and Theoretically Estimated Orientational Distributions of Solutes at the Air/Water Interface Achintya Kundu; Hidekazu Watanabe; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY C,
Volume：117,
Number：17,
First page：8887,
Last page：8891, May 2013,
[Reviewed]Linear and nonlinear polarization-sensitive spectroscopic techniques are employed to determine the orientational distributions of solute molecules adsorbed at the air/water interface. Each solute molecule shows very broad orientational distribution with a standard deviation ranging from 16 degrees to 21 degrees. The experimentally determined orientational distributions are well reproduced by classical molecular dynamics simulations. The good agreement between experimental results and theoretical calculations enables us to elucidate how the orientational distribution at the air/water interface is controlled by the chemical structure of the solute molecules.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jp402674uDOI ID：10.1021/jp402674u,
ISSN：1932-7447,
ORCID：28499900,
Web of Science ID：WOS:000318536600034 Computational analysis of the quadrupole contribution in the second-harmonic generation spectroscopy for the water/vapor interface (vol 138, 064704, 2013) Kazuya Shiratori; Shoichi Yamaguchi; Tahei Tahara; Akihiro Morita
JOURNAL OF CHEMICAL PHYSICS,
Volume：138,
Number：15, Apr. 2013,
[Reviewed]AMER INST PHYSICS, English
DOI：https://doi.org/10.1063/1.4802916DOI ID：10.1063/1.4802916,
ISSN：0021-9606,
ORCID：28499903,
Web of Science ID：WOS:000317814900047 Computational analysis of the quadrupole contribution in the second-harmonic generation spectroscopy for the water/vapor interface Shiratori Kazuya; Shoichi Yamaguchi; Tahei Tahara; Akihiro Morita
JOURNAL OF CHEMICAL PHYSICS,
Volume：138,
Number：6, Feb. 2013,
[Reviewed]Second-order susceptibility for water/vapor interface is calculated theoretically using molecular dynamics simulation, which considers both the dipole and quadrupole contributions. We find that the nonresonant second harmonic generation (SHG) signal is dominated by the quadrupole contribution from the bulk. We also elucidate the fact that the nonresonant susceptibility tends to be negative in general, irrespective of the molecular orientation. The present argument for SHG is commonly applicable to the nonresonant vibrational sum-frequency generation (SFG) spectra, and should be valid for other liquid interfaces. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790407]
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.4790407DOI ID：10.1063/1.4790407,
ISSN：0021-9606,
eISSN：1089-7690,
ORCID：28499902,
Web of Science ID：WOS:000315054400035 Structure and Dynamics of Interfacial Water Studied by Heterodyne-Detected Vibrational Sum-Frequency Generation Satoshi Nihonyanagi; Jahur A. Mondal; Shoichi Yamaguchi; Tahei Tahara
ANNUAL REVIEW OF PHYSICAL CHEMISTRY, VOL 64,
Volume：64,
First page：579,
Last page：603, 2013,
[Reviewed]Vibrational sum-frequency generation (VSFG) spectroscopy is a powerful tool to study interfaces. Recently, multiplex heterodyne-detected VSFG (HD-VSFG) has been developed, which enables the direct measurement of complex second-order nonlinear susceptibility [chi((2))]. HD-VSFG has remarkable advantages over conventional VSFG. For example, the imaginary part of chi((2)) [Im chi((2))] obtained with this interferometric technique is the direct counterpart to the infrared [Im chi((1))] and Raman [Im chi((3))] spectra in the bulk, and it is free from the spectral deformation inevitable in conventional VSFG [vertical bar chi((2)vertical bar 2)] spectra. The Im chi((2)) signal is obtained with a sign that contains unambiguous information about the up/down orientation of interfacial molecules. Furthermore, HD-VSFG can be straightforwardly extended to time-resolved measurements when combined with photoexcitation. In this review, we describe the present status of experiments and applications of multiplex HD-VSFG spectroscopy, in particular with regard to the orientation and structure of interfacial water at charged, neutral, and biorelevant water interfaces.
ANNUAL REVIEWS, English, In book
DOI：https://doi.org/10.1146/annurev-physchem-040412-110138DOI ID：10.1146/annurev-physchem-040412-110138,
ISSN：0066-426X,
ORCID：28499904,
Web of Science ID：WOS:000321771600026 Communication: Quantitative estimate of the water surface pH using heterodyne-detected electronic sum frequency generation Shoichi Yamaguchi; Achintya Kundu; Pratik Sen; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：137,
Number：15, Oct. 2012,
[Reviewed]Most chemical reactions in water are very sensitive to pH. Many environmentally important chemical reactions are known to take place at the water surface (i.e., air/water interface). However, the pH of the water surface is still controversial. Spectroscopic experiments and theoretical calculations indicate that the water surface is more acidic than the bulk, whereas electrophoretic experiments provide a contrary view. Here, we report that a novel nonlinear optical experiment with a surface-active pH indicator can quantitatively evaluate the pH of the water surface. The result clearly shows that the pH of the water surface is lower than that of the bulk by 1.7. This is the first study to apply a principle of bulk pH measurements to the water surface, and therefore provides a reliable experimental estimate for the pH difference between the water surface and bulk. It is considered that the higher acidity of the water surface plays a key role in marine and atmospheric chemical reactions. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4758805]
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.4758805DOI ID：10.1063/1.4758805,
ISSN：0021-9606,
ORCID：28499906,
Web of Science ID：WOS:000310307100001 Ultrafast vibrational dynamics of water at a charged interface revealed by two-dimensional heterodyne-detected vibrational sum frequency generation Prashant Chandra Singh; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：137,
Number：9, Sep. 2012,
[Reviewed]Two-dimensional heterodyne-detected vibrational sum frequency generation (2D HD-VSFG) spectroscopy is performed for an aqueous interface for the first time. The 2D HD-VSFG spectra in the OH stretch region are obtained from a positively charged surfactant/water interface with isotopically diluted water (HOD/D2O) to reveal the femtosecond vibrational dynamics of water at the charged interface. The 2D HD-VSFG spectrum is diagonally elongated immediately after photoexcitation, clearly demonstrating inhomogeneity in the interfacial water. This elongation almost disappears at 300 fs owing to the spectral diffusion. Interestingly, the 2D HD-VSFG spectrum at the 0 fs shows an oppositely asymmetric shape to the corresponding 2D IR spectrum in bulk water: The bandwidth of the bleach signal gets narrower when the pump wavenumber becomes higher. This suggests that the dynamics and mechanism of the hydrogen bond rearrangement at the charged interface are significantly different from those in bulk water. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4747828]
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.4747828DOI ID：10.1063/1.4747828,
ISSN：0021-9606,
eISSN：1089-7690,
ORCID：28499909,
Web of Science ID：WOS:000309092000045 Ultrafast Vibrational Dynamics of a Charged Aqueous Interface by Femtosecond Time-Resolved Heterodyne-Detected Vibrational Sum Frequency Generation Satoshi Nihonyanagi; Prashant C. Singh; Shoichi Yamaguchi; Tahei Tahara
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN,
Volume：85,
Number：7,
First page：758,
Last page：760, Jul. 2012,
[Reviewed]Newly developed time-, frequency-, and phase-resolved heterodyne-detected vibrational sum frequency generation (TR-HD-VSFG) spectroscopy opens a new door to explore ultrafast vibrational dynamics of interfacial water. Here, we present the first observation of TR-HD-VSFG spectra of water at a charged monolayer/aqueous solution interface.
CHEMICAL SOC JAPAN, English, Scientific journal
DOI：https://doi.org/10.1246/bcsj.20120051DOI ID：10.1246/bcsj.20120051,
ISSN：0009-2673,
eISSN：1348-0634,
ORCID：28499908,
Web of Science ID：WOS:000307797100004 Three Distinct Water Structures at a Zwitterionic Lipid/Water Interface Revealed by Heterodyne-Detected Vibrational Sum Frequency Generation Jahur A. Mondal; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,
Volume：134,
Number：18,
First page：7842,
Last page：7850, May 2012,
[Reviewed]Lipid/water interfaces and associated interfacial water are vital for various biochemical reactions, but the molecular-level understanding of their property is very limited. We investigated the water structure at a zwitterionic lipid, phosphatidylcholine, monolayer/water interface using heterodyne-detected vibrational sum frequency generation spectroscopy. Isotopically diluted water was utilized in the experiments to minimize the effect of intra/intermolecular couplings. It was found that the OH stretch band in the Im chi((2)) spectrum of the phosphatidylcholine/water interface exhibits a characteristic double-peaked feature. To interpret this peculiar spectrum of the zwitterionic lipid/water interface, Im chi((2)) spectra of a zwitterionic surfactant/water interface and mixed lipid/water interfaces were measured, The Im chi((2)) spectrum of the zwitterionic surfactant/water interface clearly shows both positive and negative bands in the OH stretch region, revealing that multiple water structures exist at the interface. At the mixed lipid/water interfaces, while gradually varying the fraction of the anionic and cationic lipids, we observed a drastic change in the Im chi((2)) spectra in which spectral features similar to those of the anionic, zwitterionic, and cationic lipid/water interfaces appeared successively. These observations demonstrate that, when the positive and negative charges coexist at the interface, the H-down-oriented water structure and H-up-oriented water structure appear in the vicinity of the respective charged sites. In addition, it was found that a positive Im chi((2)) appears around 3600 cm(-1) for all the monolayer interfaces examined, indicating weakly interacting water species existing in the hydrophobic region of the monolayer at the interface. On the basis of these results, we concluded that the characteristic Im chi((2)) spectrum of the zwitterionic lipid/water interface arises from three different types of water existing at the interface: (1) the water associated with the negatively charged phosphate, which is strongly H-bonded and has a net H-up orientation, (2) the water around the positively charged choline, which forms weaker H-bonds and has a net H-down orientation, and (3) the water weakly interacting with the hydrophobic region of the lipid, which has a net H-up orientation.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/ja300658hDOI ID：10.1021/ja300658h,
ISSN：0002-7863,
ORCID：28499907,
Web of Science ID：WOS:000303696200045 "Up" versus "down" alignment and hydration structures of solutes at the air/water interface revealed by heterodyne-detected electronic sum frequency generation with classical molecular dynamics simulation Shoichi Yamaguchi; Hidekazu Watanabe; Sudip Kumar Mondal; Achintya Kundu; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：135,
Number：19, Nov. 2011,
[Reviewed]We unambiguously demonstrate the "up" versus "down" alignment of a pair of prototypical solute molecules adsorbed at the air/water interface for the first time using heterodyne-detected electronic sum frequency generation spectroscopy. This molecular alignment is also reproduced by classical molecular dynamics (MD) simulation theoretically. Furthermore, the MD simulation indicates distinctly different interface-specific hydration structures around the two solute molecules, which dictate the molecular alignment at the interface. It is concluded that the hydrophilicity difference between the terminal functional groups of the solute governs the molecular orientation and surrounding hydration structures at the interface. (C) 2011 American Institute of Physics. [doi:10.1063/1.3662136]
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.3662136DOI ID：10.1063/1.3662136,
ISSN：0021-9606,
ORCID：28499910,
Web of Science ID：WOS:000297473300038 Unified Molecular View of the Air/Water Interface Based on Experimental and Theoretical chi((2)) Spectra of an Isotopically Diluted Water Surface Satoshi Nihonyanagi; Tatsuya Ishiyama; Touk-kwan Lee; Shoichi Yamaguchi; Mischa Bonn; Akihiro Morita; Tahei Tahara
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,
Volume：133,
Number：42,
First page：16875,
Last page：16880, Oct. 2011,
[Reviewed]The energetically unfavorable termination of the hydrogen-bonded network of water molecules at the air/water interface causes molecular rearrangement to minimize the free energy. The long-standing question is how water minimizes the surface free energy. The combination of advanced, surface-specific nonlinear spectroscopy and theoretical simulation provides new insights. The complex chi((2)) spectra of isotopically diluted water surfaces obtained by heterodyne-detected sum frequency generation spectroscopy and molecular dynamics simulation show excellent agreement, assuring the validity of the microscopic picture given in the simulation. The present study indicates that there is no ice-like structure at the surface in other words, there is no increase of tetrahedrally coordinated structure compared to the bulk but that there are water pairs interacting with a strong hydrogen bond at the outermost surface. Intuitively, this can be considered a consequence of the lack of a hydrogen bond toward the upper gas phase, enhancing the lateral interaction at the boundary. This study also confirms that the major source of the isotope effect on the water chi((2)) spectra is the intramolecular anharmonic coupling, i.e., Fermi resonance.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/ja2053754DOI ID：10.1021/ja2053754,
ISSN：0002-7863,
ORCID：28499914,
Web of Science ID：WOS:000296678200035 Electric quadrupole contribution to the nonresonant background of sum frequency generation at air/liquid interfaces Shoichi Yamaguchi; Kazuya Shiratori; Akihiro Morita; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：134,
Number：18,
First page：7, May 2011,
[Reviewed]We study an electric quadrupole contribution to sum frequency generation (SFG) at air/liquid interfaces in an electronically and vibrationally nonresonant condition. Heterodyne-detected electronic sum frequency generation spectroscopy of air/liquid interfaces reveals that nonresonant chi((2)) (second-order nonlinear susceptibility) has a negative sign and nearly the same value for all eight liquids studied. This result is rationalized on the basis of the theoretical expressions of chi((2)) with an electric quadrupole contribution taken into account. It is concluded that the nonresonant background of SFG is predominantly due to interfacial nonlinear polarization having a quadrupole contribution. Although this nonlinear polarization is localized at the interface, it depends on quadrupolar chi((2)) in the bulk as well as that at the interface. It means that the sign of nonresonant chi((2)) bears no relation to the "up" versus "down" alignment of interfacial molecules, because nonresonant chi((2)) has a quadrupolar origin. (C) 2011 American Institute of Physics. [doi:10.1063/1.3586811]
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.3586811DOI ID：10.1063/1.3586811,
ISSN：0021-9606,
ORCID：28499912,
Web of Science ID：WOS:000290589900037 Acid-Base Equilibrium at an Aqueous Interface: pH Spectrometry by Heterodyne-Detected Electronic Sum Frequency Generation Shoichi Yamaguchi; Kankan Bhattacharyya; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY C,
Volume：115,
Number：10,
First page：4168,
Last page：4173, Mar. 2011,
[Reviewed]We applied interface-selective heterodyne-detected electronic sum frequency generation (HD-ESFG) to the pH Spectrometry of an air/cationic surfactant/water interface in order to obtain insight into an acid - base equilibrium at the interface. We used an indicator molecule adsorbed at the interface to probe local pH and local effective polarity. We obtained unprecedentedly high quality spectral data of the interfacial pH spectrometry, which clearly indicates that this interface has higher pH than the bulk owing to the positive charge of the head group of the surfactant. In addition, we found that the air/surfactant/water interface and the micelle interface of the Same surfactant are essentially equivalent in local pH and local effective polarity.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jp1113174DOI ID：10.1021/jp1113174,
ISSN：1932-7447,
eISSN：1932-7455,
ORCID：28499911,
Web of Science ID：WOS:000288113400042 Molecules at the Air/Water Interface Experience a More Inhomogeneous Solvation Environment than in Bulk Solvents: A Quantitative Band Shape Analysis of Interfacial Electronic Spectra Obtained by HD-ESFG Sudip Kumar Mondal; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY C,
Volume：115,
Number：7,
First page：3083,
Last page：3089, Feb. 2011,
[Reviewed]To evaluate the inhomogeneity of the solvation environment at the air/water interface, we quantitatively analyzed the shape of the electronic spectra at the air/water interface for the first time. We measured the interface-selective electronic chi((2)) (second-order nonlinear susceptibility) spectra of solvatochromic coumarin molecules at the air/water interface by heterodyne-detected electronic sum frequency generation (HD-ESFG) spectroscopy. The observed imaginary chi((2)) (Im[chi((2))]) spectra were well reproduced by the convolution of a line shape function with a Gaussian distribution of a frequency shift, which enabled us to quantitatively determine the peal: position and bandwidth of the Im[chi((2))] spectra. The effective polarity of the air/water interface, which was determined by the peak position, was found to be dependent on each coumarin, which agreed with our previous homodyne-detected ESFG study. Interestingly, the spectra at the air/water interface showed substantially broader bandwidths than those in equally polar bulk solvents or even bulk water, indicating that the solvation environment at the air/water interface is more inhomogeneous than that in bulk solvents. At the air/water interface, the stabilization energy of the solvation not only changes with the change of the position and orientation of the surrounding solvents but also varies with the change of the position and orientation of the solute at the interface. We consider that this unique situation arising from the anisotropy along interface normal brings about a broader distribution of the stabilization energy of solvation at the air/water interface. The present work showed that the air/water interface provides a more inhomogeneous solvation environment than equally polar bulk solvents because of this broader distribution of the local solvation structure at the interface.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jp110456tDOI ID：10.1021/jp110456t,
ISSN：1932-7447,
ORCID：28499913,
Web of Science ID：WOS:000287338100023 Physisorption Gives Narrower Orientational Distribution than Chemisorption on a Glass Surface: A Polarization-Sensitive Linear and Nonlinear Optical Study Shoichi Yamaguchi; Haruko Hosoi; Megumi Yamashita; Pratik Sen; Tahei Taharat
JOURNAL OF PHYSICAL CHEMISTRY LETTERS,
Volume：1,
Number：18,
First page：2662,
Last page：2665, Sep. 2010,
[Reviewed]Linear and nonlinear polarization-sensitive spectroscopic techniques were employed to determine the orientational distribution of a probe molecule physisorbed and chemisorbed On a fused-silica glass surface.. The chemisorption was through a well-known specific reaction between the maleimide group of the probe molecule and the thiol group of the surface. In the physisorption, the molecule was bound-to the surface by the weaker van der Waals forces, dipole-dipole interaction, or both. Despite the absence of the strong interaction between the molecule and the surface in the physisorption, it was found that the physisorption gives narrower orientational distribution than the chemisorption. The strong covalent bond in the chemisorption is not effective to increase the orientational order. It is highly likely that the present conclusion is applicable to a variety of probe molecules having a functional group for a specific reaction of chemisorption.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jz101142mDOI ID：10.1021/jz101142m,
ISSN：1948-7185,
ORCID：28499916,
Web of Science ID：WOS:000282017400008 Structure and Orientation of Water at Charged Lipid Monolayer/Water Interfaces Probed by Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy Jahur A. Mondal; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,
Volume：132,
Number：31,
First page：10656,
Last page：10657, Aug. 2010,
[Reviewed]Cell membrane/water interfaces provide a unique environment for many biochemical reactions, and associated interfacial water is an integral part of such reactions. A molecular level understanding of the structure and orientation of water at lipid/water interfaces is required to realize the complex chemistry at biointerfaces. Here we report the heterodyne-detected vibrational sum frequency generation (HD-VSFG) studies of lipid monolayer/water interfaces. At charged lipid/water interfaces, the orientation of interfacial water is governed by the net charge on the lipid head-group; at an anionic lipid/water interface, water is in the hydrogen-up orientation, and at the cationic lipid/water interface, water is in the hydrogen-down orientation. At the cationic and anionic lipid/water interfaces, interfacial water has comparable hydrogen bond strength, and it is analogous to the bulk water.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/ja104327tDOI ID：10.1021/ja104327t,
ISSN：0002-7863,
ORCID：28499917,
Web of Science ID：WOS:000280692200015 Water Hydrogen Bond Structure near Highly Charged Interfaces Is Not Like Ice Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,
Volume：132,
Number：20,
First page：6867,
Last page：+, May 2010,
[Reviewed]Imaginary x((2)) spectra of HOD at air/charged surfactant/aqueous interfaces highly resemble the IR spectrum of the bulk liquid HOD, showing no indication of the "ice-like" structure. Clearly, the hydrogen bond structures at highly charged interfaces are not like ice but very similar to the structure in the bulk.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/ja910914gDOI ID：10.1021/ja910914g,
ISSN：0002-7863,
ORCID：28499919,
Web of Science ID：WOS:000277999700001 Half hydration' at the air/water interface revealed by HD-ESFG spectroscopy, polarization SHG, and MD simulation Hidekazu Watanabe; Shoichi Yamaguchi; Sobhan Sen; Akihiro Morita; Tahei Tahara
J. Chem. Phys.,
Volume：132,
Number：14,
First page：144701, Apr. 2010,
[Reviewed]English, Scientific journal
DOI：https://doi.org/10.1063/1.3372620DOI ID：10.1063/1.3372620 "Half-hydration" at the air/water interface revealed by heterodyne-detected electronic sum frequency generation spectroscopy, polarization second harmonic generation, and molecular dynamics simulation Hidekazu Watanabe; Shoichi Yamaguchi; Sobhan Sen; Akihiro Morita; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：132,
Number：14,
First page：9, Apr. 2010,
[Reviewed]A solute-solvent interaction at the air/water interface was investigated both experimentally and theoretically, by studying a prototypical surface-active polarity indicator molecule, coumarin 110 (C110), adsorbed at the air/water interface with heterodyne-detected electronic sum frequency generation (HD-ESFG) spectroscopy, polarization second harmonic generation (SHG), and a molecular dynamics (MD) simulation. The second-order nonlinear optical susceptibility (chi((2))) tensor elements of C110 at the air/water interface were determined experimentally by HD-ESFG and polarization SHG, and information on "intermediate" polarity sensed by C110 at the interface was obtained by HD-ESFG. An MD simulation and a time-dependent density functional theory calculation were used to theoretically evaluate the chi((2)) tensor elements, which were in good agreement with the experimental results of HD-ESFG and polarization SHG. The microscopic "half-hydration" structure around C110 at the water surface was visualized on the basis of the MD simulation data, with which we can intuitively understand the microscopic origin of the surface activity of C110 and the intermediate polarity sensed by C110 at the air/water interface.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.3372620DOI ID：10.1063/1.3372620,
ISSN：0021-9606,
ORCID：28499915,
Web of Science ID：WOS:000276973500028 Ultrafast dynamics of malachite green at the air/water interface studied by femtosecond time-resolved electronic sum frequency generation (TR-ESFG): an indicator for local viscosity Pratik Sen; Shoichi Yamaguchi; Tahei Tahara
FARADAY DISCUSSIONS,
Volume：145,
First page：411,
Last page：428, 2010,
[Reviewed]The ultrafast excited-state dynamics of malachite green (MG) at the air/water interface was studied with a newly-developed interface-selective nonlinear optical technique: femtosecond time-resolved electronic sum frequency generation (TR-ESFG) spectroscopy. MG is known as a viscosity indicator because of its well-known viscosity-dependent dynamics in bulk solution. Femtosecond time-resolved electronic spectra of MG at the interface were obtained with nearly the same quality as that of conventional time-resolved absorption spectra in the bulk. The time constants of the ground-state recovery at the air/water interface were determined and compared with those in bulk glycerol-water mixtures. It was found that the ground-state recovery of MG at the air/water interface is much slower than that in bulk water and almost equivalent to that in the glycerol-water mixture containing glycerol volume fractions as high as 65-80%. This result indicates higher local viscosity at the interface than in bulk water. However, it is possible that changes of the molecular properties, e.g. a change of shape of the potential energy surface, of MG at the interface also contribute to the apparently very large viscosity values evaluated. On the basis of the present results, we discuss the applicability of probe molecules to evaluate the physicochemical properties of the liquid interface and note the importance of the extrinsic and intrinsic factors that make the chemical process at liquid interfaces different from that in bulk solution.
ROYAL SOC CHEMISTRY, English, Scientific journal
DOI：https://doi.org/10.1039/b908097jDOI ID：10.1039/b908097j,
ISSN：1364-5498,
ORCID：28499918,
Web of Science ID：WOS:000273708000022 Direct evidence for orientational flip-flop of water molecules at charged interfaces: A heterodyne-detected vibrational sum frequency generation study Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：130,
Number：20,
First page：5, May 2009,
[Reviewed]Complex chi((2)) spectra of air/water interfaces in the presence of charged surfactants were measured by heterodyne-detected broadband vibrational sum frequency generation spectroscopy for the first time. In contrast to the neat water surface, the signs of chi((2)) for two broad OH bands are the same in the presence of the charged surfactants. The obtained chi((2)) spectra clearly showed flip-flop of the interfacial water molecules which is induced by the opposite charge of the head group of the surfactants. With the sign of beta((2)) theoretically obtained, the absolute orientation, i.e., up/down orientation, of water molecules at the charged aqueous surfaces was uniquely determined by the relation between the sign of chi((2)) and the molecular orientation angle. Water molecules orient with their hydrogen up at the negatively charged aqueous interface whereas their oxygen up at the positively charged aqueous interface.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.3135147DOI ID：10.1063/1.3135147,
ISSN：0021-9606,
eISSN：1089-7690,
ORCID：28499921,
Web of Science ID：WOS:000266500200043 Ultrafast Dynamics at Liquid Interfaces Investigated with Femtosecond Time-Resolved Multiplex Electronic Sum-Frequency Generation (TR-ESFG) Spectroscopy
Kentaro Sekiguchi; Shoichi Yamaguchi; Tahei Tahara
ULTRAFAST PHENOMENA XVI, Volume：92, First page：520, Last page：522, 2009, [Reviewed]
We developed a new nonlinear spectroscopy, femtosecond time-resolved electronic sum-frequency generation (TR-ESFG) spectroscopy, to investigate ultrafast dynamics at liquid interfaces. Transient electronic spectra at the air/water interface were obtained for the first time.
SPRINGER-VERLAG BERLIN, English, International conference proceedings
ISSN：0172-6218, Web of Science ID：WOS:000282108000169
Different Molecules Experience Different Polarities at the Air/Water Interface Sobhan Sen; Shoichi Yamaguchi; Tahei Tahara
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION,
Volume：48,
Number：35,
First page：6439,
Last page：6442, 2009,
[Reviewed]WILEY-V C H VERLAG GMBH, English, Scientific journal
DOI：https://doi.org/10.1002/anie.200901094DOI ID：10.1002/anie.200901094,
ISSN：1433-7851,
ORCID：28499920,
Web of Science ID：WOS:000269239700012 Coherent acoustic phonons in a thin gold film probed by femtosecond surface plasmon resonance Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF RAMAN SPECTROSCOPY,
Volume：39,
Number：11,
First page：1703,
Last page：1706, Nov. 2008,
[Reviewed]We report on coherent phonon detection in a thin gold film by a new femtosecond pump-probe surface plasmon resonance (SPR) technique. Acoustic coherent phonons are generated impulsively in the gold film on a prism, and they are detected in the time domain through the reflectivity modulation for probe pulses that satisfy the SPR condition. We observed not only the fundamental vibration of a longitudinal acoustic phonon but also the overtones up to the fourth. Copyright (C) 2008 John Wiley & Sons, Ltd.
JOHN WILEY & SONS LTD, English, Scientific journal
DOI：https://doi.org/10.1002/jrs.2078DOI ID：10.1002/jrs.2078,
ISSN：0377-0486,
ORCID：28499922,
Web of Science ID：WOS:000261206200027 New Insight into the Surface Denaturation of Proteins: Electronic Sum Frequency Generation Study of Cytochrome c at Water Interfaces Pratik Sen; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY B,
Volume：112,
Number：43,
First page：13473,
Last page：13475, Oct. 2008,
[Reviewed]In situ characterization of Surface denaturation of a protein was realized by newly developed interface-selective multiplex electronic sum frequency generation spectroscopy. The observed electronic spectra of cytochrome c at the air/water interface exhibited a broad feature, which demonstrated coexistence of the nativelike and denatured protein at the interface. This situation of the mixed conformation at the air/water interface did not change in the acidic condition of pH = 2 where the protein was completely denatured in the bulk water. In sharp contrast, only native spectrum was observed at the silica/water interface.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jp8061288DOI ID：10.1021/jp8061288,
ISSN：1520-6106,
ORCID：28499926,
Web of Science ID：WOS:000260357700002 Heterodyne-detected electronic sum frequency generation: "Up" versus "down" alignment of interfacial molecules Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：129,
Number：10, Sep. 2008,
[Reviewed]Heterodyne-detected electronic sum frequency generation (HD-ESFG) spectroscopy is newly developed to obtain complex electronic chi((2)) spectra of interfaces for a simultaneous detection bandwidth broader than 100 nm. HD-ESFG provides linear chi((2)) spectra that have unambiguous information on the "up" versus "down" alignment of interfacial molecules. It is demonstrated for p-nitroaniline, a prototypical molecule of nonlinear optical materials, that the up versus down alignment at an air/fused silica interface is critically influenced by a fine modification of the molecule. (c) 2008 American Institute of Physics.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.2981179DOI ID：10.1063/1.2981179,
ISSN：0021-9606,
Web of Science ID：WOS:000259883600002 Heterodyne-detected electronic sum frequency generation: "Up" versus "down" alignment of interfacial molecules Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：129,
Number：10,
First page：4, Sep. 2008,
[Reviewed]Heterodyne-detected electronic sum frequency generation (HD-ESFG) spectroscopy is newly developed to obtain complex electronic chi((2)) spectra of interfaces for a simultaneous detection bandwidth broader than 100 nm. HD-ESFG provides linear chi((2)) spectra that have unambiguous information on the "up" versus "down" alignment of interfacial molecules. It is demonstrated for p-nitroaniline, a prototypical molecule of nonlinear optical materials, that the up versus down alignment at an air/fused silica interface is critically influenced by a fine modification of the molecule. (c) 2008 American Institute of Physics.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.2981179DOI ID：10.1063/1.2981179,
ISSN：0021-9606,
ORCID：28499924,
Web of Science ID：WOS:000259883600002 PHYS 27-Hidden electronic excited state of enhanced green fluorescent protein (eGFP) by new multiplex two-photon absorption spectroscopy
Haruko Hosoi; Shoichi Yamaguchi; Hideaki Mizuno; Atsushi Miyawaki; Tahei Tahara
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Volume：235, Apr. 2008, [Reviewed]
AMER CHEMICAL SOC, English
ISSN：0065-7727, Web of Science ID：WOS:000271775108798
Novel interface-selective even-order nonlinear spectroscopy Shoichi Yamaguchi; Tahei Tahara
LASER & PHOTONICS REVIEWS,
Volume：2,
Number：1-2,
First page：74,
Last page：82, Apr. 2008,
[Reviewed]New interface-selective second- (chi((2))) and fourth-order (chi ((4))) nonlinear spectroscopic techniques have been developed. chi((2)) electronic sum frequency generation (ESFG) spectroscopy enables us to obtain interfacial electronic spectra with an unprecedented high signal-to-noise ratio and dense wavelength data points. Frequency-domain chi((4)) Raman spectroscopy provides vibrational spectra of interfaces for a very wide wavenumber range covering the whole fingerprint region. Because these new even-order electronic and vibrational nonlinear spectroscopies utilize only visible and/or near-infrared laser pulses, they are applicable to a variety of "buried" interfaces that are not readily accessed by the other existing methods.
WILEY-V C H VERLAG GMBH, English
DOI：https://doi.org/10.1002/lpor.200710027DOI ID：10.1002/lpor.200710027,
ISSN：1863-8880,
ORCID：28499927,
Web of Science ID：WOS:000255328600005 Hidden electronic excited state of enhanced green fluorescent protein Haruko Hosoi; Shoichi Yamaguchi; Hideaki Mizuno; Atsushi Miyawaki; Tahei Tahara
JOURNAL OF PHYSICAL CHEMISTRY B,
Volume：112,
Number：10,
First page：2761,
Last page：2763, Mar. 2008,
[Reviewed]Precise two-photon absorption spectra of the green fluorescent protein (GFP) and the mutants sapphire-GFP (T203I) and enhanced GFP (S65T/F64L), as well as a model compound for the chromophore, 4'-hydroxybenzylidene-2,3-dimethylimidazolinone (HBDI) were measured by multiplex two-photon absorption spectroscopy. The observed TPA bands of the anionic forms of enhanced GFP and HBDI were significantly shifted to the higher energy compared with the lowest-energy bands in one-photon absorption spectra. This result indicated the existence of a hidden electronic excited state in the vicinity of the lowest excited singlet (S I) state of the anionic form of the GFP chromophore, which is the origin of the blue shift of the two-photon absorption spectra as well as two-photon fluorescence excitation spectra.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jp711628uDOI ID：10.1021/jp711628u,
ISSN：1520-6106,
ORCID：28499925,
Web of Science ID：WOS:000253784700002 Femtosecond time-resolved electronic sum-frequency generation spectroscopy: A new method to investigate ultrafast dynamics at liquid interfaces Kentaro Sekiguchi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：128,
Number：11,
First page：8, Mar. 2008,
[Reviewed]We developed a new surface-selective time-resolved nonlinear spectroscopy, femtosecond time-resolved electronic sum-frequency generation (TR-ESFG) spectroscopy, to investigate ultrafast dynamics of molecules at liquid interfaces. Its advantage over conventional time-resolved second harmonic generation spectroscopy is that it can provide spectral information, which is realized by the multiplex detection of the transient electronic sum-frequency signal using a broadband white light continuum and a multichannel detector. We studied the photochemical dynamics of rhodamine 800 (R800) at the air/water interface with the TR-ESFG spectroscopy, and discussed the ultrafast dynamics of the molecule as thoroughly as we do for the bulk molecules with conventional transient absorption spectroscopy. We found that the relaxation dynamics of photoexcited R800 at the air/water interface exhibited three characteristic time constants of 0.32 ps, 6.4 ps, and 0.85 ns. The 0.32 ps time constant was ascribed to the lifetime of dimeric R800 in the lowest excited singlet (S(1)) state (S(1) dimer) that is directly generated by photoexcitation. The S(1) dimer dissociates to a monomer in the S(1) state (S(1) monomer) and a monomer in the ground state with this time constant. This lifetime of the S(1) dimer was ten times shorter than the corresponding lifetime in a bulk aqueous solution. The 6.4 ps and 0.85 ns components were ascribed to the decay of the S(1) monomer (as well as the recovery of the dimer in the ground state). For the 6.4 ps time constant, there is no corresponding component in the dynamics in bulk water, and it is ascribed to an interface-specific deactivation process. The 0.85 ns time constant was ascribed to the intrinsic lifetime of the S(1) monomer at the air/water interface, which is almost the same as the lifetime in bulk water. The present study clearly shows the feasibility and high potential of the TR-ESFG spectroscopy to investigate ultrafast dynamics at the interface.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.2841023DOI ID：10.1063/1.2841023,
ISSN：0021-9606,
ORCID：28499923,
Web of Science ID：WOS:000254292500065 New interface-selective even-order nonlinear spectroscopy Shoichi Yamaguchi; Tahei Tahara
2007 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS, VOLS 1-4,
First page：851,
Last page：852, 2007,
[Reviewed]New interface-selective second- (chi((2))) and fourth-order (chi((4))) nonlinear spectroscopies were developed. The chi((2)) electronic sum frequency generation spectroscopy provides precise interfacial electronic spectra. Vibrational spectra of buried interfaces are acquired in the whole fingerprint region by the chi((4)) Raman spectroscopy.
IEEE, English, International conference proceedings
DOI：https://doi.org/10.1109/CLEOPR.2007.4391513DOI ID：10.1109/CLEOPR.2007.4391513,
Web of Science ID：WOS:000256956600429 chi((4)) Raman spectroscopy for buried water interfaces Shoichi Yamaguchi; Tahei Tahara
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION,
Volume：46,
Number：40,
First page：7609,
Last page：7612, 2007,
[Reviewed]WILEY-V C H VERLAG GMBH, English, Scientific journal
DOI：https://doi.org/10.1002/anie.200701609DOI ID：10.1002/anie.200701609,
ISSN：1433-7851,
eISSN：1521-3773,
ORCID：28499928,
Web of Science ID：WOS:000250249300013 Determining electronic spectra at interfaces by electronic sum frequency generation: One- and two-photon double resonant oxazine 750 at the air/water interface Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：125,
Number：19,
First page：8, Nov. 2006,
[Reviewed]The second-order nonlinear electronic spectra were measured for a dye oxazine 750 (OX750) adsorbed at the air/water interface using the multiplex electronic sum frequency generation (ESFG) spectroscopy recently developed by our group. The excitation-wavelength dependence of the ESFG spectrum was investigated, and a global fitting analysis was performed to separate contributions of one- and two-photon resonances. The analysis yielded linear interface electronic spectra in the one- and two-photon resonance regions, which can be directly compared to bulk absorption spectra. A two-dimensional plot of the linear interface electronic spectra is newly proposed to graphically represent all the essential information on the electronic structure of interfacial molecules. On this new analytical basis of the ESFG spectroscopy, the spectroscopic properties of OX750 at the interface are discussed. (c) 2006 American Institute of Physics.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.2375093DOI ID：10.1063/1.2375093,
ISSN：0021-9606,
ORCID：28499929,
Web of Science ID：WOS:000242181800074 Formation and dissociation of rhodamine 800 dimers in water: Steady-state and ultrafast spectroscopic study K Sekiguchi; S Yamaguchi; T Tahara
JOURNAL OF PHYSICAL CHEMISTRY A,
Volume：110,
Number：8,
First page：2601,
Last page：2606, Mar. 2006,
[Reviewed]We investigated the fundamental photophysics and photochemistry of a cationic dye rhodamine 800 (R800) in water using steady-state and ultrafast time-resolved spectroscopies. In the ground state, the monomer and dimer coexist in equilibrium, which causes significant concentration dependence of UV-visible (vis) absorption spectra. We determined the equilibrium constant as well as the molar absorption spectra of the monomer and dimer from a global fitting analysis of the UV-vis spectra. The obtained pure dimer spectrum indicates that it is a nonparallel H-dimer. In contrast to the absorption spectra, the steady-state fluorescence spectra do not show any noticeable concentration dependence. The fluorescence lifetime was determined as 0.73 ns regardless of the concentration, and the fluorescence of R800 in water was solely attributed to the monomer. In femtosecond time-resolved absorption measurements, we observed the S-n <- S-1 absorption bands of the monomer and the dimer, as well as the ground-state bleaching signals. It was found that the S-1 dimer dissociates to produce the S-1 monomer (and the S-0 monomer) or relaxes to the So dimer with a time constant of as short as 3.0 ps, which brings about the absence of dimer fluorescence.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jp055027pDOI ID：10.1021/jp055027p,
ISSN：1089-5639,
ORCID：28499930,
Web of Science ID：WOS:000235943700005 Multiplex electronic sum frequency generation spectroscopy of dye molecules at the air/water interface Shoichi Yamaguchi; Kentaro Sekiguchi; Tahei Tahara
Femtochemistry VII,
First page：245,
Last page：248, 2006,
[Reviewed]This chapter describes multiplex electronic sum frequency generation spectroscopy and its application to the studies of static and dynamic properties of dye molecules adsorbed at the air-water interface. Second-order nonlinear spectroscopy is a powerful tool to study the structure and dynamics of molecules at interfaces that are very important in fundamental science and industrial application. Vibrational spectra of interfacial molecules are measured by IR-visible sum frequency generation (SFG) spectroscopy. The sensitivity of the IR-vis SFG spectroscopy has improved by using broadband IR pulses and multichannel detectors. High-quality IR-vis SFG spectra can be measured nowadays. On the other hand, second-order nonlinear susceptibility data of interfacial molecules are measured by the resonance second harmonic generation (SHG) method. In the spectral measurements, the SHG light intensity is recorded point by point with scanning the fundamental excitation wavelength. It is difficult to measure high-quality electronic spectra of interfacial molecules by the conventional scanning method. © 2006 Elsevier B.V. All rights reserved.
Elsevier, English, In book
DOI：https://doi.org/10.1016/B978-044452821-6/50036-8DOI ID：10.1016/B978-044452821-6/50036-8,
SCOPUS ID：84882502327 Interface-specific chi((4)) coherent Raman spectroscopy in the frequency domain S Yamaguchi; T Tahara
JOURNAL OF PHYSICAL CHEMISTRY B,
Volume：109,
Number：51,
First page：24211,
Last page：24214, Dec. 2005,
[Reviewed]We demonstrate interface-specific fourth-order (chi((4))) coherent Raman spectroscopy in the frequency domain for the first time. Because the chi((4)) Raman spectroscopy uses only visible (vis) or near-IR light, it is expected to be a potential alternative to the widely utilized IR-vis sum frequency generation spectroscopy that cannot be applied to interfaces buried in thick IR absorbers such as water. We present the vibrational vertical bar chi((4))vertical bar(2) spectrum of rhodamine 800 at the air/water interface in a wide spectral range 100-3600 cm(-1). Comparison of the vertical bar chi((4))vertical bar(2) spectrum with the vertical bar chi((3))vertical bar(2) spectrum leads us to conclude that the present chi((4)) spectroscopy successfully probes the interface distinguished clearly from the bulk.
AMER CHEMICAL SOC, English
DOI：https://doi.org/10.1021/jp0542064DOI ID：10.1021/jp0542064,
ISSN：1520-6106,
ORCID：28499932,
Web of Science ID：WOS:000234259900001 Relaxation dynamics of the hydrated electron: Femtosecond time-resolved resonance Raman and luminescence study M Mizuno; S Yamaguchi; T Tahara
JOURNAL OF PHYSICAL CHEMISTRY A,
Volume：109,
Number：24,
First page：5257,
Last page：5265, Jun. 2005,
[Reviewed]Femtosecond time-resolved resonance Raman measurements were carried out to examine the relaxation process of the hydrated electron in water. The rise of the intra- and intermolecular vibrational Raman bands of the solvating water molecules was successfully time-resolved with a time resolution as high as 250 fs. The temporal intensity change of Raman bands, as well as that of luminescence background, was compared with the time evolution of the transient absorption signal. It was found that (1) the Raman and luminescence signals exhibited the same temporal behavior, (2) the rise time of the Raman bands is faster than the appearance of the equilibrated hydrated electron, indicating that the precursor state also gives rise to resonance Raman signals, and (3) the rise of the transient Raman band is slower than that of the transient absorption at the probe wavelength of 800 nm. Because it has been shown that the Raman intensity enhancement arises from the resonance with the s -> p transition, fact 2 implies that the precursor state is the nonequilibrated s-state electron. The delayed rise of the Raman signal compared to the absorption was explained in terms of the temporal change of the resonance condition. In very early time when the absorption is largely red-shifted, the probe at 800 nm is resonant with the high energy part of the absorption that provides little resonance Raman enhancement. This explanation was consistent with the probe wavelength dependence of the temporal behavior of the Raman signal: the Raman bands measured with the higher energy probe (600 nm) rose even more slowly. The resonance Raman signal in the anti-Stokes side was also examined, but no anti-Stokes band was observable. It suggests that the temperature increase of the solvation structure around the nonequilibrated hydrated electron is less than 100 K.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jp050828dDOI ID：10.1021/jp050828d,
ISSN：1089-5639,
ORCID：28499933,
Web of Science ID：WOS:000229866900003 Host to guest energy transfer in a self-assembled supramolecular nanocage observed by picosecond fluorescence quenching H Hosoi; S Yamaguchi; T Tahara
CHEMISTRY LETTERS,
Volume：34,
Number：4,
First page：618,
Last page：619, Apr. 2005,
[Reviewed]The host-guest energy transfer process in a self-assembled system was investigated by picosecond time-resolved fluorescence spectroscopy. A self-assembled coordination nanocage (Pd6L4) was photoexcited and the appearance of the fluorescence from an encapsulated guest acridine dye molecule was observed. The time constant (1.3 ns) as well as the efficiency (9%) of the energy transfer from the nanocage to the guest molecule was determined.
CHEMICAL SOC JAPAN, English, Scientific journal
DOI：https://doi.org/10.1246/cl.2005.618DOI ID：10.1246/cl.2005.618,
ISSN：0366-7022,
eISSN：1348-0715,
ORCID：28499931,
Web of Science ID：WOS:000228541600081 Precise electronic X-(2) spectra of molecules adsorbed at an interface measured by multiplex sum frequency generation S Yamaguchi; T Tahara
JOURNAL OF PHYSICAL CHEMISTRY B,
Volume：108,
Number：50,
First page：19079,
Last page：19082, Dec. 2004,
[Reviewed]We have developed a new technique to obtain a second-order nonlinear (chi((2))) electronic spectrum of molecules adsorbed at an interface. This technique is based on multiplex sum frequency generation that utilizes femtosecond near-infrared pulses and white light continuum. We obtained the \X-(2)\(2) spectra of a dye Nile Blue (NB) at the air/water interface with an unprecedented high signal-to-noise ratio and dense wavelength data points. Fitting analyses with an exact chi((2)) expression were performed for the spectra, and detailed information about the electronic structure of NB at the interface was obtained.
AMER CHEMICAL SOC, English
DOI：https://doi.org/10.1021/jp045306xDOI ID：10.1021/jp045306x,
ISSN：1520-6106,
ORCID：28499935,
Web of Science ID：WOS:000225695100001 Observation of an optically forbidden state of C-60 by nondegenerate two-photon absorption spectroscopy S Yamaguchi; T Tahara
CHEMICAL PHYSICS LETTERS,
Volume：390,
Number：1-3,
First page：136,
Last page：139, May 2004,
[Reviewed]Two-photon absorption (TPA) spectra of C-60 in toluene were measured for it wide wavelength region from 270 to 680 nm by femtosecond pump-probe nondegenerate TPA spectroscopy. A distinct TPA band peaked at 314 nm was observed, and its intensity was evaluated to be 80 GM. The depolarization ratio of the TPA band was found to be zero within the experimental uncertainty, which indicates that this band is due to a totally symmetric (A(g)) two-photon allowed excited state. The energy of the observed A(g) state is about 1 eV below a prediction based on the theoretically calculated pi-electron energies. (C) 2004 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, English, Scientific journal
DOI：https://doi.org/10.1016/j.cplett.2004.03.146DOI ID：10.1016/j.cplett.2004.03.146,
ISSN：0009-2614,
ORCID：28499934,
Web of Science ID：WOS:000221628400025 Femtosecond dynamics of the solvated electron in water studied by time-resolved Raman spectroscopy
M Mizuno; S Yamaguchi; T Tahara
FEMTOCHEMISTRY AND FEMTOBIOLOGY: ULTRAFAST EVENTS IN MOLECULAR SCIENCE, First page：225, Last page：228, 2004, [Reviewed]
ELSEVIER SCIENCE BV, English, International conference proceedings
Web of Science ID：WOS:000222945300044
Two-photon absorption spectrum of all-trans retinal S Yamaguchi; T Tahara
CHEMICAL PHYSICS LETTERS,
Volume：376,
Number：1-2,
First page：237,
Last page：243, Jul. 2003,
[Reviewed]The nondegenerate two-photon absorption spectrum of all-traps retinal in a nonpolar solvent at room temperature has been measured for the first time. The multichannel detection utilizing the technique of femtosecond time-resolved pump-probe absorption spectroscopy has enabled us to obtain precise two-photon absorption spectra. It was found that the two-photon absorption maximum of all-traps retinal is located at 376 nm, which is 7 nm longer than the one-photon absorption peak. This peak wavelength difference indicates the 500-cm(-1) energy gap between the S-3 (B-u) state and the S-2 (A(g)) state. On the basis of the obtained two-photon absorption data and the available fluorescence data, we determined the 0-0 position of the S-2 state to be 2.47 x 10(4) cm(-1). (C) 2003 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, English, Scientific journal
DOI：https://doi.org/10.1016/S0009-2614(03)00984-9DOI ID：10.1016/S0009-2614(03)00984-9,
ISSN：0009-2614,
ORCID：28499936,
Web of Science ID：WOS:000184315600037 Oxidative cyclization of bis(biaryl)acetylenes: Synthesis and photophysics of dibenzo[g,p]chrysene-based fluorescent polymers S Yamaguchi; TM Swager
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,
Volume：123,
Number：48,
First page：12087,
Last page：12088, Dec. 2001,
[Reviewed]AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/ja016692oDOI ID：10.1021/ja016692o,
ISSN：0002-7863,
Web of Science ID：WOS:000172591000031 Spectroscopic determination of very low quantum yield of singlet oxygen formation photosensitized by industrial dyes S Yamaguchi; Y Sasaki
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY,
Volume：142,
Number：1,
First page：47,
Last page：50, Aug. 2001,
[Reviewed]We have measured the quantum yield Q(Delta) of (1)Delta (g) molecular oxygen (singlet oxygen, O-1(2)) formation photosensitized by some industrial dyes. As regards dyes and pigments for practical uses, it is widely believed that O-1(2) is a key intermediate in their photofading processes. Q(Delta) for practical dyes, however, is generally very low, and it has been difficult to determine accurately Q(Delta) for them. We have made a highly sensitive spectrometer for 1.27 mum O-1(2) phosphorescence detection, and determined Q(Delta) for an azo dye as low as (2.2 +/- 1.5) X 10(-5). This is the first demonstration of Q(Delta) lower than 10(-4). (C) 2001 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE SA, English, Scientific journal
DOI：https://doi.org/10.1016/S1010-6030(01)00470-1DOI：https://doi.org/10.1016/s1010-6030(01)00470-1DOI ID：10.1016/S1010-6030(01)00470-1,
ISSN：1010-6030,
ORCID：28499937,
Web of Science ID：WOS:000170672600007 Effect of water on primary photocarrier-generation process in Y-form titanyl phthalocyanine S Yamaguchi; Y Sasaki
JOURNAL OF PHYSICAL CHEMISTRY B,
Volume：104,
Number：39,
First page：9225,
Last page：9229, Oct. 2000,
[Reviewed]We have studied the effect of adsorbed water on the primary photocarrier-generation process in Y-form titanyl phthalocyanine (Y-TiOPc) by using ground:state absorption and time-resolved fluorescence spectroscopy. The water adsorption is the unique feature of Y-TiOPc, which is not observed in the other polymorphs of TiOPc. We report for the first time the water-induced change of the absorption spectrum, that is, the hydrochromism of Y-TiOPc. The fluorescence lifetimes and amplitudes of Y-TiOPc are greatly influenced by adsorbed water. We have found that the mechanism of the fluorescence quenching of Y-TiOPc caused by water adsorption is the same as that by an electric field. Adsorbed water enhances the photocarrier generation of Y-TiOPc in the same way as an electric field does in the picosecond time regime.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jp0019557DOI ID：10.1021/jp0019557,
ISSN：1089-5647,
ORCID：28499939,
Web of Science ID：WOS:000089712900023 Construction of electric-field-modulated picosecond time-resolved fluorescence spectrometer S Yamaguchi; Y Sasaki
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS,
Volume：39,
Number：10,
First page：6107,
Last page：6108, Oct. 2000,
[Reviewed]We have developed a new electric-field-modulated picosecond time-resolved fluorescence spectrometer using a streak scope. We can obtain an electric-field-induced change of a fluorescence lifetime and that of an amplitude as low as 1% without losing the two-dimensional multichannel advantage of the streak scope. The spectrometer enabled us to observe electric-field-induced fluorescence quenching of titanyl phthalocyanine and obtain valuable information on the mechanism of photocarrier generation.
INST PURE APPLIED PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1143/JJAP.39.6107DOI ID：10.1143/JJAP.39.6107,
ISSN：0021-4922,
ORCID：28499938,
Web of Science ID：WOS:000090139000076 Primary carrier-generation process in Y-form and phase I titanyl phthalocyanines S Yamaguchi; Y Sasaki
CHEMICAL PHYSICS LETTERS,
Volume：323,
Number：1-2,
First page：35,
Last page：42, Jun. 2000,
[Reviewed]We have studied the primary process of the photocarrier generation in Y-form and phase I titanyl phthalocyanine (TiOPc) microcrystallites using the electric-field-modulated picosecond time-resolved fluorescence spectroscopy. The electric-field dependence of the fluorescence amplitudes and lifetimes of TiOPcs leads to a detailed understanding of excited-state charge-transfer (CT) character. We have concluded that only the shorter-lifetime singlet exciton of the Y-form has significant CT character. We regard the CT exciton as a key to the high photocarrier-generation quantum yield of the Y-form. The lack of a CT state in phase I TiOPc causes its low photosensitivity. (C) 2000 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, English, Scientific journal
DOI：https://doi.org/10.1016/S0009-2614(00)00475-9DOI：https://doi.org/10.1016/s0009-2614(00)00475-9DOI ID：10.1016/S0009-2614(00)00475-9,
ISSN：0009-2614,
ORCID：28499940,
Web of Science ID：WOS:000087538200006 Ultrafast electronic relaxation and hydrogen-bond-formation/dissociation dynamics of photoexcited all-trans retinal in protic solvents S Yamaguchi; H Hamaguchi
JOURNAL OF PHYSICAL CHEMISTRY A,
Volume：104,
Number：18,
First page：4272,
Last page：4279, May 2000,
[Reviewed]The ultrafast electronic relaxation and the hydrogen-bond-formation/dissociation dynamics of photoexcited all-trans retinal in 1-butanol/cyclohexane mixed solvents have been studied by femtosecond time-resolved visible absorption spectroscopy. Four transient absorption bands, which can be assigned to the S-3, S-2, S-1, and T-1 states, were observed in neat cyclohexane. The shapes and the dynamics of these absorption bands agree very well with those reported previously for all-trans retinal in hexane. In contrast, only three transient absorption bands, which can be assigned to the S-3, S-2, and T-1 states, were identified in the mixed solvents. The band assigned to the S-2 State showed a time-dependent peak shift, which is attributed to solvent reorganization on a picosecond time scale. A kinetic analysis of the three transient absorption bands has led to the conclusion that no state-ordering change of the (n, pi*) and (pi, pi*) states takes place in the excited singlet manifold upon hydrogen-bond formation. The l-butanol concentration dependence of the absorption spectra shows that the free and hydrogen-bonded species coexist in the S-3 and T-1 states, but that all of the retinal molecules are hydrogen-bonded in the S-2 state. These observations indicate that an ultrafast hydrogen bond-formation reaction takes place during or just after the S-3 --> S-2 internal conversion and is complete within a time scale much shorter than the S-2 lifetime. Dissociation of the hydrogen bonding is most likely to take place during or after the S-1 --> T-1 intersystem crossing and is complete within a time scale much shorter than the T-1 lifetime. The observed longer lifetime of the hydrogen-bonded S-2 State is consistent with the higher isomerization quantum yield in protic solvents than in aprotic nonpolar solvents.
AMER CHEMICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1021/jp993551oDOI ID：10.1021/jp993551o,
ISSN：1089-5639,
ORCID：28499941,
Web of Science ID：WOS:000087003100019 Primary process of photocarrier generation in Y-form titanyl phthalocyanine studied by electric-field-modulated picosecond time-resolved fluorescence spectroscopy S Yamaguchi; Y Sasaki
JOURNAL OF PHYSICAL CHEMISTRY B,
Volume：103,
Number：33,
First page：6835,
Last page：6838, Aug. 1999,
[Reviewed]We have investigated the primary process of the carrier generation in Y-form titanyl phthalocyanine (Y-TiOPc) microcrystallites by means of newly developed electric-field-modulated picosecond time-resolved fluorescence spectroscopy. Two singlet excitons have been identified in the fluorescence decay curves of Y-TiOPc. We have inferred from the field-dependence of the fluorescence amplitudes and lifetimes that the shorter-lifetime exciton of intramolecular charge transfer (CT) character is a primary intermediate in the carrier generation process. It has been found that the internal conversion from the CT exciton to the Frenkel exciton is decelerated by the electric field.
AMER CHEMICAL SOC, English
DOI：https://doi.org/10.1021/jp991892wDOI ID：10.1021/jp991892w,
ISSN：1089-5647,
ORCID：28499942,
Web of Science ID：WOS:000082335600001 Two distinct solvated structures of para-nitroaniline in acetonitrile and their dissociation and reassociation dynamics K Mohanalingam; S Yamaguchi; H Hamaguchi
LASER CHEMISTRY,
Volume：19,
Number：1-4,
First page：329,
Last page：333, 1999,
[Reviewed]We have measured the femtosecond time-resolved absorption spectra of para-nitroaniline in acetonitrile just after the photoexcitation to the lowest excited singlet state. The Singular Value Decomposition (SVD) analysis shows that two temporal evolutions follow the photoexcitation. The fast component (0.7 ps time constant) describes the dissociation of the 1:2 associated form to generate the 1:0 form followed by its reassociation with AN molecules. A slower temporal evolution of 10 ps is most likely to represent the cooling down process of the whole system.
TAYLOR & FRANCIS LTD, English, Scientific journal
DOI：https://doi.org/10.1155/1999/63925DOI ID：10.1155/1999/63925,
ISSN：0278-6273,
ORCID：28499943,
Web of Science ID：WOS:000081370000058 Femtosecond ultraviolet-visible absorption study of all-trans -> 13-cis center dot 9-cis photoisomerization of retinal S Yamaguchi; H Hamaguchi
JOURNAL OF CHEMICAL PHYSICS,
Volume：109,
Number：4,
First page：1397,
Last page：1408, Jul. 1998,
[Reviewed]The all-trans --> 13-cis.9-cis photoisomerization reaction of retinal in aerated nonpolar solvents has been studied by femtosecond time-resolved ultraviolet-visible (UV-VIS) absorption spectroscopy. The excited-state absorption spectra in the wavelength region 400-800 nm indicate that there is no all-trans --> 13-cis.9-cis isomerization reaction pathway that is complete in the electronic excited singlet manifold of S-1, S-2, and S-3. The ground-state bleaching recovery of all-trans retinal monitored in the near UV (ultraviolet) wavelength region 310-390 nm shows that a perpendicular excited singlet state (p*) takes part in the all-trans --> 13-cis.9-cis isomerization reaction. The lifetime of p* is about 7 ps, and the precursor of p* is most probably the S-2 state. The isomerization quantum yield derived from the femtosecond UV absorption data agrees well with those determined by the HPLC analysis of the photoproduct. The temperature dependence of the isomerization quantum yield indicates the existence of a potential-energy barrier as high as (1.2 +/- 0.6) x 10(3) cm(-1) on the reaction pathway from the S-2 state to the p* state. (C) 1998 American Institute of Physics.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.476692DOI ID：10.1063/1.476692,
ISSN：0021-9606,
ORCID：28499944,
Web of Science ID：WOS:000075255600025 Femtosecond visible absorption study of excited-state dynamics of 9-cis retinal S Yamaguchi; H Hamaguchi
CHEMICAL PHYSICS LETTERS,
Volume：287,
Number：5-6,
First page：694,
Last page：700, May 1998,
[Reviewed]Femtosecond time-resolved pump-probe absorption spectroscopy has been used to study the photophysics and photochemistry of 9-cis retinal in aerated hexane. Three excited singlet states (S-3, S-2, S-1) and the lowest tripler start (T-1) have been identified by the SVD analysis of the observed time-resolved absorption spectra. No evidence has been obtained for a 9-cis --> all-trans isomerization reaction pathway that completes in the excited singlet manifold. (C) 1998 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, English, Scientific journal
DOI：https://doi.org/10.1016/S0009-2614(98)00234-6DOI：https://doi.org/10.1016/s0009-2614(98)00234-6DOI ID：10.1016/S0009-2614(98)00234-6,
ISSN：0009-2614,
ORCID：28499945,
Web of Science ID：WOS:000073718500035 Femtosecond time-resolved absorption spectroscopy of all-trans-retinal in hexane S Yamaguchi; HO Hamaguchi
JOURNAL OF MOLECULAR STRUCTURE,
Volume：379,
First page：87,
Last page：92, Jun. 1996,
[Reviewed]We have carried out femtosecond time-resolved absorption measurements of all-trans-retinal in hexane. The S-n <-- S-2 and the T-n <-- T-1 absorption spectra with corresponding temporal evolutions have been obtained by a kinetic analysis based on singular value decomposition (SVD).
ELSEVIER SCIENCE BV, English, Scientific journal
DOI：https://doi.org/10.1016/0022-2860(95)09178-5DOI ID：10.1016/0022-2860(95)09178-5,
ISSN：0022-2860,
ORCID：28499947,
Web of Science ID：WOS:A1996UQ82400010 Exciton dynamics in poly(p-pyridyl vinylene) JW Blatchford; SW Jessen; LB Lin; JJ Lih; TL Gustafson; AJ Epstein; DK Fu; MJ Marsella; TM Swager; AG MacDiarmid; S Yamaguchi; H Hamaguchi
PHYSICAL REVIEW LETTERS,
Volume：76,
Number：9,
First page：1513,
Last page：1516, Feb. 1996,
[Reviewed]We present results of picosecond photoinduced absorption (PA) and time-resolved photoluminescence studies on solid and solution forms of poly(p-pyridyl vinylene). The nearly identical PA response of all forms of the polymer reflects the generation of the same primary photoexcitation, a Couloumbically bound intrachain singlet exciton, and the absence of exotic species such as interchain excimers. The time dependence of the PA points to direct intersystem crossing as the origin of triplet excitons, ruling out generation of free carriers as a precursor to exciton formation.
AMERICAN PHYSICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1103/PhysRevLett.76.1513DOI ID：10.1103/PhysRevLett.76.1513,
ISSN：0031-9007,
ORCID：28499946,
Web of Science ID：WOS:A1996TW70000028 CONVENIENT METHOD OF MEASURING THE CHIRP STRUCTURE OF FEMTOSECOND WHITE-LIGHT CONTINUUM PULSES S YAMAGUCHI; HO HAMAGUCHI
APPLIED SPECTROSCOPY,
Volume：49,
Number：10,
First page：1513,
Last page：1515, Oct. 1995,
[Reviewed]We have developed a convenient method of measuring the temporal chirp structure of white-light continuum pulses used in femtosecond time-resolved absorption spectroscopy. This method, based on the nonresonant optical Kerr effect, is superior in many respects to the existing one that uses the sum or difference frequency generation by a nonlinear crystal.
SOC APPLIED SPECTROSCOPY, English, Scientific journal
DOI：https://doi.org/10.1366/0003702953965434DOI ID：10.1366/0003702953965434,
ISSN：0003-7028,
ORCID：28499948,
Web of Science ID：WOS:A1995TD15400018 ULTRAFAST VIBRATIONAL-RELAXATION IN PHOTOGENERATED S(1) ALPHA-TERTHIOPHENE IN SOLUTION BY FEMTOSECOND TIME-RESOLVED ABSORPTION EMISSION AND PICOSECOND TIME-RESOLVED RAMAN-SPECTROSCOPY S YAMAGUCHI; H HAMAGUCHI
CHEMICAL PHYSICS LETTERS,
Volume：227,
Number：3,
First page：255,
Last page：260, Sep. 1994,
[Reviewed]Ultrafast vibrational population redistribution dynamics and subsequent cooling processes have been identified and quantified for photogenerated S1 alpha-terthiophene in solution by using femtosecond time-resolved absorption/emission spectroscopy combined with picosecond time-resolved Raman spectroscopy. The population redistribution among the S1 vibrational levels dominates the dynamics for the first few picoseconds after the photoexcitation. The cooling of the solvent-solute system then takes place in the time scale of a few tens of picoseconds.
ELSEVIER SCIENCE BV, English, Scientific journal
DOI：https://doi.org/10.1016/0009-2614(94)00832-9DOI ID：10.1016/0009-2614(94)00832-9,
ISSN：0009-2614,
eISSN：1873-4448,
ORCID：28499949,
Web of Science ID：WOS:A1994PF45600004 Picosecond dynamics of photoexcited transient species of p-phenylenes; Population decay and structural chance
S YAMAGUCHI; H HAMAGUCHI
FOURTEENTH INTERNATIONAL CONFERENCE ON RAMAN SPECTROSCOPY, First page：496, Last page：497, 1994, [Reviewed]
JOHN WILEY & SONS LTD, English, International conference proceedings
Web of Science ID：WOS:A1994BD55D00225
CONSTRUCTION OF A TRANSFORM-LIMITED PICOSECOND TIME-RESOLVED RAMAN SPECTROMETER K IWATA; S YAMAGUCHI; H HAMAGUCHI
REVIEW OF SCIENTIFIC INSTRUMENTS,
Volume：64,
Number：8,
First page：2140,
Last page：2146, Aug. 1993,
[Reviewed]A pump-probe picosecond time-resolved Raman spectrometer has been constructed using a dye laser synchronously pumped by a cw mode-locked Nd:YAG laser and a high repetition rate (2 kHz) dye amplifier pumped by the frequency doubled output from a cw Nd:YAG regenerative amplifier. Transform-limited picosecond pulses with 3.5 cm-1 wave number width and 3.2 ps temporal width are obtained at the wavelength of 588 nm. The second harmonic of these pulses is generated at 294 nm and is used for pumping, while the remaining visible pulses are used for probing. resonance Raman scattering. The cross-correlation time between the pump and probe pulses is 4.1 ps. The temporal profile of the laser pulse is found to be very close to the sech2 shape. The wave number resolution of the system is estimated to be 3.5 cm-1 according to the Tailor criterion. The time resolution is estimated to be 2.2 ps using a criterion newly proposed in the present paper. Time-resolved Raman spectra of S1 trans-stilbene and S1 p-terphenyl are presented to demonstrate the capability of the constructed spectrometer.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.1143951DOI ID：10.1063/1.1143951,
ISSN：0034-6748,
ORCID：28499950,
Web of Science ID：WOS:A1993LR97900006
Leaflet-specific Lipid Diffusion Revealed by Fluorescence Lifetime Correlation Analyses Takuhiro Otosu; Shoichi Yamaguchi
CHEMISTRY LETTERS,
Volume：49,
Number：12,
First page：1473,
Last page：1480, Dec. 2020
Cell membranes are fluidic, and the fluidic properties give unique biological functions to the membranes. Here, we review the application of fluorescence lifetime correlation analyses to elucidate the leaflet-specific lipid diffusion in a model cell membrane supported on a glass surface. Utilization of fluorescence lifetime enables us to discriminate the signals from each leaflet of the lipid bilayer and to analyze the lipid diffusion in a leaflet-specific manner. The results showed that the lipid diffusion in a proximal leaflet facing a glass surface is sensitive to the strength of the electrostatic interaction between the lipid headgroup and the glass surface whereas that in the distal one is insensitive to it. This clearly indicates that the interleaflet coupling is negligible. Because the strength of the interleaflet coupling is highly relevant to the cooperative formation of functional domains across the bilayer, this work provides an important insight into the lipid dynamics in cell membranes.
CHEMICAL SOC JAPAN, English, Book review
DOI：https://doi.org/10.1246/cl.200539DOI ID：10.1246/cl.200539,
ISSN：0366-7022,
eISSN：1348-0715,
Web of Science ID：WOS:000598377200011 Comment on "Phase-sensitive sum frequency vibrational spectroscopic study of air/water interfaces: H2O, D2O, and diluted isotopic mixtures" [J. Chem. Phys. 150, 144701 (2019)] Mohammed Ahmed; Yuki Nojima; Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
JOURNAL OF CHEMICAL PHYSICS,
Volume：152,
Number：23, Jun. 2020
AMER INST PHYSICS, English, Others
DOI：https://doi.org/10.1063/1.5126062DOI ID：10.1063/1.5126062,
ISSN：0021-9606,
eISSN：1089-7690,
Web of Science ID：WOS:000542728800001 Two-Dimensional Fluorescence Lifetime Correlation Spectroscopy: Concepts and Applications Takuhiro Otosu; Shoichi Yamaguchi
MOLECULES,
Volume：23,
Number：11, Nov. 2018
We review the basic concepts and recent applications of two-dimensional fluorescence lifetime correlation spectroscopy (2D FLCS), which is the extension of fluorescence correlation spectroscopy (FCS) to analyze the correlation of fluorescence lifetime in addition to fluorescence intensity. Fluorescence lifetime is sensitive to the microenvironment and can be a "molecular ruler" when combined with FRET. Utilization of fluorescence lifetime in 2D FLCS thus enables us to quantify the inhomogeneity of the system and the interconversion dynamics among different species with a higher time resolution than other single-molecule techniques. Recent applications of 2D FLCS to various biological systems demonstrate that 2D FLCS is a unique and promising tool to quantitatively analyze the microsecond conformational dynamics of macromolecules at the single-molecule level.
MDPI, English, Book review
DOI：https://doi.org/10.3390/molecules23112972DOI ID：10.3390/molecules23112972,
eISSN：1420-3049,
Web of Science ID：WOS:000451641900244 Ultrafast Dynamics at Water Interfaces Studied by Vibrational Sum Frequency Generation Spectroscopy Satoshi Nihonyanagi; Shoichi Yamaguchi; Tahei Tahara
CHEMICAL REVIEWS,
Volume：117,
Number：16,
First page：10665,
Last page：10693, Aug. 2017
We present an overview of studies on the ultrafast dynamics of water at aqueous interfaces carried out by time-resolved vibrational sum frequency generation (VSFG) spectroscopies. This research field has been growing rapidly, stimulated by technical developments achieved recently. In this review, first, the principles and instrumentations are described for conventional VSFG, heterodyne-detected VSFG, and various IR-pump/VSFG-probe techniques, namely, time-resolved conventional VSFG, time-resolved heterodyne-detected VSFG, and their extension to two-dimensional spectroscopy. Second, the applications of these time-resolved VSFG techniques to the study of the femtosecond vibrational dynamics of water at various interfaces are discussed, in the order of silica/water, charged monolayer/water, and the air/water interfaces. These studies demonstrate that there exists water dynamics specific to the interfaces and that time-resolved VSFG spectroscopies can unambiguously detect such unique dynamics in an interface-selective manner. In particular, the most recent time-resolved heterodyne detected VSFG and two-dimensional heterodyne-detected VSFG unveil the inhomogeneity of the hydrogen bond arid relevant vibrational dynamics of interfacial water through unambiguous observation of hole-burning in the OH stretch band, as well as the subsequent spectral diffusion in the femtosecond time region. These time-resolved VSFG studies have also left several issues for discussion. We describe not only the obtained conclusive physical insights into interfacial water dynamics but also the points left unclear or controversial. A new type of experiment that utilizes UV excitation is also described briefly. Lastly, the summary and some future perspectives of time-resolved VSFG spectroscopies are given.
AMER CHEMICAL SOC, English, Book review
DOI：https://doi.org/10.1021/acs.chemrev.6b00728DOI ID：10.1021/acs.chemrev.6b00728,
ISSN：0009-2665,
eISSN：1520-6890,
Web of Science ID：WOS:000408519200003 Standing evanescent-wave fluorescence correlation spectroscopy for analyzing the translational diffusion in bio-membranes
Takuhiro Otosu; Shoichi Yamaguchi
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Volume：252, Aug. 2016
AMER CHEMICAL SOC, English, Summary international conference
ISSN：0065-7727, Web of Science ID：WOS:000431460201108
Ultrafast Vibrational Dynamics of Water at a Zwitterionic Lipid/Water Interface Revealed by Two-Dimensional Heterodyne-Detected Vibrational Sum Frequency Generation (2D HD-VSFG) Inoue Ken-ichi; Singh Prashant Chandra; Nihonyanagi Satoshi; Yamaguchi Shoichi; Tahara Tahei
ULTRAFAST PHENOMENA XIX,
Volume：162,
First page：309,
Last page：312, 2015,
[Reviewed]DOI：https://doi.org/10.1007/978-3-319-13242-6_75DOI ID：10.1007/978-3-319-13242-6_75,
ISSN：0930-8989,
Web of Science ID：WOS:000357738800075 Ultrafast Vibrational Dynamics of Water Interfaces Revealed by Time-Resolved Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy INOUE Ken-ichi; SINGH Prashant C; NIHONYANAGI Satoshi; YAMAGUCHI Shoichi; TAHARA Tahei
J. Surf. Sci. Soc. Jpn.,
Volume：35,
Number：12,
First page：662,
Last page：667, 2014
Molecular-level understanding of interfaces is of crucial importance in many fundamental and applied sciences. Vibrational sum frequency generation (VSFG) spectroscopy has intrinsic interface-selectivity and has been widely utilized to study molecular structures and dynamics at interfaces. However, conventional VSFG spectroscopy measures the intensity of the signal, providing only information about the square of second-order nonlinear susceptibility, |<I>χ</I><sup>(2)</sup>|<sup>2</sup>. Recently, we developed multiplex heterodyne-detected (HD-) VSFG spectroscopy. This HD-VSFG spectroscopy enables us to measure the imaginary part of <I>χ</I><sup>(2)</sup>, Im<I>χ</I><sup>(2)</sup>, which can be directly compared to infrared absorption and Raman spectra. Moreover, we have extended the HD-VSFG spectroscopy to time-resolved (TR-) HD-VSFG spectroscopy and two-dimensional (2D) HD-VSFG spectroscopy by combining with the pump-probe technique. This review describes development of these time-resolved HD-VSFG methods and their applications to the water interfaces.
The Surface Science Society of Japan, Japanese
DOI：https://doi.org/10.1380/jsssj.35.662DOI ID：10.1380/jsssj.35.662,
ISSN：0388-5321,
CiNii Articles ID：130004785031 Heterodyne-Detection of Vibrational Sum Frequency Generation and Local Molecular Structures at Liquid Interfaces
NIHONYANAGI Satoshi; YAMAGUCHI Shoichi; MONDAL Jahur A.; TAHARA Tahei
Japanese journal of optics, Volume：40, Number：8, First page：415, Last page：420, 10 Aug. 2011
Japanese
ISSN：0389-6625, CiNii Articles ID：10029467817, CiNii Books ID：AN00080324
PHYS 351-Ultrafast dynamics at the air/water interface investigated with time-resolved electronic sum-frequency generation (TR-ESFG) spectroscopy
Kentaro Sekiguchi; Shoichi Yamaguchi; Tahei Tahara
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Volume：235, Apr. 2008
AMER CHEMICAL SOC, English, Summary international conference
ISSN：0065-7727, Web of Science ID：WOS:000271775109234
Novel even-order nonlinear spectroscopy for liquid interfaces: Interface-specific hydrogen bonds and interfacial polarity
Shoichi Yamaguchi; Sobhan Sen; Tahei Tahara
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Volume：233, Mar. 2007
AMER CHEMICAL SOC, English, Summary international conference
ISSN：0065-7727, Web of Science ID：WOS:000207722807310
Precise two-photon absorption measurements of biomolecules using femtosecond broadband pulses.
S Yamaguchi; T Tahara
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Volume：226, First page：U333, Last page：U333, Sep. 2003
AMER CHEMICAL SOC, English, Summary international conference
ISSN：0065-7727, Web of Science ID：WOS:000187062501700
水/水，水/氷，氷/氷界面の構造とダイナミクス
01 Apr. 2022 - 31 Mar. 2027
Grant amount(Total)：17290000, Direct funding：13300000, Indirect funding：3990000
Grant number：22H02027
アミロイド形成を促す脂質‐蛋白質間相互作用の分子機構解明
01 Apr. 2019 - 31 Mar. 2023
Grant amount(Total)：15600000, Direct funding：12000000, Indirect funding：3600000
Grant number：19H02669
Structure and Dynamics of Single-Crystalline Ice Ih Interfaces
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2018 - 31 Mar. 2022
Yamaguchi Shoichi, Saitama University
Grant amount(Total)：17160000, Direct funding：13200000, Indirect funding：3960000
Among numerous crystalline phases of ice, the Ih phase is the most stable above 72 K at atmospheric pressure. It is well established that the orientations of water molecules in the bulk of ice Ih are statistical without long-range order. However, the orientational order of water at the surface of ice Ih has been enigmatic. Here we show that the surface of ice Ih at 100 K has hydrogen order with the OH group pointing upward to the air ("H-up" orientation). We applied nonlinear optical spectroscopy and theoretical modeling to the surface of isotopically pure and diluted ice Ih and observed OH stretch vibrational signatures attributed to H-up ordering. Furthermore, we found that this hydrogen order takes place despite more inhomogeneous microenvironment at the surface than in the bulk. Our results suggest the prominent role of the surface to allow the reorientation of water molecules for hydrogen ordering that is virtually prohibited in the bulk.
Grant number：18H01934
Transition states of interfacial chemical reactions revealed by novel interface-selective even-order nonlinear spectroscopy
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 10 Jul. 2015 - 31 Mar. 2018
Yamaguchi Shoichi, Saitama University
Grant amount(Total)：18070000, Direct funding：13900000, Indirect funding：4170000
Among numerous crystalline phases of ice, the Ih phase is the most stable at atmospheric pressure. It is well established that the orientations of water molecules in the bulk of ice Ih are disordered or random within the ice rules. However, the orientational order of water at surfaces of ice Ih is yet to be established. Although surface proton order of ice Ih has been investigated and suggested by some theoretical studies, no experimental evidence has been reported so far because of the lack of suitable techniques. Here we show that the surfaces of ice Ih definitely have proton order with the OH group pointing upward to the air. We applied an advanced spectroscopic technique to the ice surfaces at ca. 130 K and observed vibrational signatures of the OH stretch that directly indicate H-up orientation of water. Furthermore, we found that this surface proton order takes place irrespective of the faces of ice.
Grant number：15KT0056
Study of Complex Molecular Systems by Ultrafast and Nonlinear Spectroscopy
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), 28 Jun. 2013 - 31 Mar. 2018
TAHARA Tahei; NIHONYANAGI Satoshi; KURAMOCHI Hikaru, Institute of Physical and Chemical Research
Grant amount(Total)：141050000, Direct funding：108500000, Indirect funding：32550000
We studied complex molecular systems by the best spectroscopic measurements. We made numerous research achievements, while strongly promoting collaboration with researchers in this project. Particularly, (1) in ultrafast spectroscopy, we have realized an “ultimate” form of time-resolved impulsive stimulated Raman spectroscopy that we developed. We also clarified the ultrafast process of various biomolecules, supramolecules and functional molecules. (2) In interface-selective nonlinear spectroscopy, we have investigated interfacial water structure by utilizing heterodyne-detected vibrational sum-frequency generation spectroscopy (HD-VSFG)developed by us．We also studied interfacial dynamics by developing two-dimensional HD-VSFG spectroscopy and time-resolved measurement with ultraviolet excitation. (3) In the study of single molecule spectroscopy, we developed 2D fluorescence lifetime correlation spectroscopy, We studied protein folding processes, and obtained new important findings.
Grant number：25104005
Development of single-channel heterodyne-detected sum frequency generation spectroscopy and its application to interface physicochemistry
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research, 01 Apr. 2015 - 31 Mar. 2017
YAMAGUCHI Shoichi, Saitama University
Grant amount(Total)：3900000, Direct funding：3000000, Indirect funding：900000
Single-channel heterodyne-detected sum frequency generation (HD-SFG) spectroscopy for selectively measuring vibrational spectra of liquid interfaces is presented. This new methodology is based on optical interference between sum frequency signal light from a sample interface and phase-controlled local oscillator light. In single-channel HD-SFG, interferometric and spectrometric measurements are simultaneously carried out with an input IR laser scanned in a certain wavenumber range, which results in a less task than existing phase-sensitive sum frequency spectroscopy. The real and imaginary parts of second-order nonlinear optical susceptibility (χ(2)) of interfaces are separately obtained with spectral resolution as high as 4 cm-1 that is approximately six times better than existing multiplex HD-SFG.
Grant number：15K13616
Development of HD-SFG for buried interfaces and its application
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 01 Apr. 2013 - 31 Mar. 2016
YAMAGUCHI Shoichi
Grant amount(Total)：18850000, Direct funding：14500000, Indirect funding：4350000
Heterodyne-detected sum frequency generation (HD-SFG) has been applied only to "unburied" interfaces such as air/liquid and air/solid interfaces, because the optically-thick bulk makes it difficult to determine the phase of an electric field, which hinders the heterodyne detection. Here we report that HD-SFG for "buried" interfaces can be carried out by the precise measurement of the bulk thickness and the rigorous expression of the signal electric field.
Grant number：25288014
Development of New Interface-Selective Nonlinear Spectroscopy and Its Application to the Study of Dynamics at Liquid Interfaces
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), 01 Apr. 2012 - 31 Mar. 2015
TAHARA Tahei; YAMAGUCHI Shoichi; ISHIYAMA Tatsuya, The Institute of Physical and Chemical Research
Grant amount(Total)：46150000, Direct funding：35500000, Indirect funding：10650000
Because interfaces play crucial roles in many phenomena that are important in a wide range of science and technology, molecular-level understanding of interfaces is highly desired. In this study, we developed new interface-selective time-resolved nonlinear vibrational spectroscopic methods, by combining the femtosecond photoexcitation and multiplex heterodyne-detected vibrational sum-frequency generation technique developed by us. Using the newly developed methods, we succeeded in tracing femtosecond-picosecond dynamics at water interfaces, including the observation of hole-burning indicating inhomogeneity of hydrogen bonds of interfacial water as well as the following spectral diffusion that occurs on the time scale of a few hundred femtoseconds.
Grant number：24245006
Protein Structure Analysis by Second-order Nonlinear Spectroscopy
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 2010 - 2012
YAMAGUCHI Shoichi; HOSOI Haruko, The Institute of Physical and Chemical Research
Grant amount(Total)：19890000, Direct funding：15300000, Indirect funding：4590000
I show that a newly-developed second-order nonlinear spectroscopic technique allows me to draw topology diagrams of such proteins. Uniquely, one can determine "up" versus "down" alignment of molecules on a surface using this second-order nonlinear spectroscopy. In my novel but simple approach, an "alignment indicator" is introduced to each segment of a protein before immobilizing the protein on a glass surface, and the up versus down alignment of each segment is nonlinear-spectroscopically determined. This approach is very powerful and useful for proteins to which neither X-ray nor NMR is applicable.
Grant number：22350014
Study of complex molecular systems by advanced molecular spectroscopy
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research on Priority Areas, 2007 - 2011
TAHARA Tahei; TAKEUCHI Satoshi; YAMAGUCHI Shoichi; ISHII Kunihiko; HOSOI Haruko; MORITA Akihiro; ASANO Motoko, The Institute of Physical and Chemical Research
Grant amount(Total)：81600000, Direct funding：81600000
We studied complex molecular systems using the most advanced spectroscopy. With ultrafast spectroscopy, we elucidated the multi-dimensional reaction coordinate of isomeriataion of cis-stilbene, clarified the mechanism of the ultrafast structural chang of Cu(I) complexes, and succeeded in tracking nuclear motion along the isomerization coordinate of a prototypical cyanine dye. With interface-selective nonlinear spectroscopy, we developed heterodyne-detected electronic and vibrational sum-frequency generation spectroscopies and obtained a number of new insights into fundamental phenomena at water interfaces including the interface of model membranes. For correlation spectroscopy, we combined fluorescence intensity correlation measurements and fluorescence lifetime measurements to develop a new method that has a very high potential for the study of structural fluctuation of biopolymers.
Grant number：19056009
Exploring new molecular science at interfaces by novel nonlinear spectroscopy Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), 2007 - 2009
TAHARA Tahei; YAMAGUCHI Shoichi; ISHII Kunihiko; WATANABE Hidekazu, The Institute of Physical and Chemical Research
Grant amount(Total)：47970000,
Direct funding：36900000,
Indirect funding：11070000On the basis of our original ESFG spectroscopy, we have developed a group of new interface-selective nonlinear electronic and vibrational spectroscopies such as time-resolved ESFG (TR-ESFG), 4^
-order nonlinear Raman (X^<(4)> Raman), heterodyne-detected ESFG (HD-ESFG) and heterodyne-detected VSFG (HD-VSFG). Using these new methods, we studied fundamental problems of water interfaces. We clarified the effective polarity, surface denaturation of a protein, ultrafast dynamics of dye molecule, novel hydrogen bonding at the water interfaces, and observed flip-flop of water molecules at the charged water interfaces.
Grant number：19205005DNAの二次構造転移の観測
2003 - 2005
Grant amount(Total)：3800000, Direct funding：3800000
Grant number：15750023 Real-time observation and control of the condensed-phase photochemical dynamics using optimized ultrashort optical pulses
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), 2001 - 2003
TAHARA Tahei; YAMAGUCHI Shoichi; TAKEUCHI Satoshi
Grant amount(Total)：14200000, Direct funding：14200000
We studied photochemical dynamics in the condensed phase by using femtosecond electronic spectroscopy, picosecond time-resolved vibrational spectroscopy, and pump-probe spectroscopy that enables us to observe nuclear wavepacket motions. Major outcomes are followings.
1.Ultrafast photodissociation of diphenylcyclopropenone was studied by pump-probe spectroscopy based on 10-fs pulses. The wavepacket motion of the S_2 state was observed, and its relevance to the reaction coordinate was discussed. Time-resolved time-domain Raman spectroscopy was developed. With this method, we observed Raman-active low-frequency vibrations of trans-stilbene and binapthyl in the excited state in the time domain.
2.Photo-induced proton transfer of the 7-azaindole dimer and photoisomerization of trans-azobenzene were studied by femtosecond time-resolved spectroscopy, and their reaction mechanisms were clarified. Ultrafast fluorescence dynamics of a model compound of chromophore of Green Fluorescence Protein was investigated, and its ultrafast radiationless relaxation process was discussed.
3.Picosecond time-resolved Raman spectra of water were measured under the resonance condition with the electronic transition of the solvated electron. It was discovered that the water molecules that solvate the electron give rise to strong resonance Raman scattering.
4.Fluorescence up-conversion microscope was developed. It simultaneously achieved femtosecond time-resolution and sub-micron space-resolution in fluorescence measurements for the first time. A new femtosecond fluorescence imaging technique was developed, which enabled us to observe fluorescence intensity as a time-wavelength two-dimensional image. An apparatus for multi-channel detection of two-photon absorption was developed. Precise two photon absorption spectra of retinal and C_<60> were measured.
Grant number：13440183 熱による誘電場操作と化学反応の制御
1996 - 1998
Grant amount(Total)：35000000, Direct funding：35000000
Grant number：08404038 フェムト秒円2色分光計の製作とその軸性不斉分子の光ラセミ化測定への応用
1996 - 1996
Grant amount(Total)：1200000, Direct funding：1200000
Grant number：08740447 |
mail.saitama-u.ac.jp