A5051016526- Spectroscopy and Quantum Chemical Studies
- Advanced Chemical Physics Studies
- Photochemistry and Electron Transfer Studies
- Spectroscopy and Laser Applications
- Thermodynamic properties of mixtures
- Molecular spectroscopy and chirality
- Electrochemical Analysis and Applications
- Atmospheric Ozone and Climate
- Chemical and Physical Properties in Aqueous Solutions
- nanoparticles nucleation surface interactions
- Solid-state spectroscopy and crystallography
- Atmospheric chemistry and aerosols
- Quantum, superfluid, helium dynamics
- Molecular Spectroscopy and Structure
- Neurobiology and Insect Physiology Research
- Electrostatics and Colloid Interactions
- Metallurgy and Material Science
- Thermochemical Biomass Conversion Processes
- Neutrophil, Myeloperoxidase and Oxidative Mechanisms
- Nanopore and Nanochannel Transport Studies
- Antifungal resistance and susceptibility
- Hemiptera Insect Studies
- Free Radicals and Antioxidants
- Protein Structure and Dynamics
- Photoreceptor and optogenetics research
Tohoku University
2016-2025
Suzuka University of Medical Science
2014-2025
Kyoto University
2013-2022
Tohoku University Hospital
2018-2022
Kobe University
2019-2021
Chiba University
2017-2021
Graduate School USA
2015-2020
Sendai University
2015-2020
Sumitomo Dainippon Pharma (Japan)
2020
Hokkaido University
2015-2018
The energetically unfavorable termination of the hydrogen-bonded network water molecules at air/water interface causes molecular rearrangement to minimize free energy. long-standing question is how minimizes surface combination advanced, surface-specific nonlinear spectroscopy and theoretical simulation provides new insights. complex χ((2)) spectra isotopically diluted surfaces obtained by heterodyne-detected sum frequency generation dynamics show excellent agreement, assuring validity...
Sum frequency generation (SFG) spectroscopy is a powerful experimental technique to probe surface structures. This paper presents new theoretical mode of nonempirical analysis SFG spectra for interfacial structures, which considerably generalizes our previous effort (Chem. Phys. 2000, 258, 371), involved several empirical elements. The method based on time correlation function the frequency-dependent hyperpolarizability, can be straightforwardly evaluated via molecular dynamics simulations...
Significance Over 150 years ago, Faraday discovered the presence of a water layer on ice below bulk melting temperature. This is important for surface chemistry and glacier sliding close to subfreezing conditions. The nature thickness this quasi-liquid has remained controversial. By combining experimental simulated surface-specific vibrational spectroscopy, shown change in noncontinuous, stepwise fashion around 257 K. Below temperature, first bilayer already molten; second melts at...
Gas−liquid interfacial structures of NaCl and NaI aqueous solutions are investigated via molecular dynamics simulations using a flexible polarizable water model we have developed. The new five-site aims at suitably describing properties, including vibrational sum frequency spectroscopy where both flexibility polarization crucial. performance the is systematically examined demonstrated by number properties bulk interface, density, vaporization energy, dipole moment, diffusion coefficient,...
A new flexible and polarizable water model based on the charge response kernel (CRK) theory is developed for analysis of sum frequency generation (SFG) spectroscopy. The CRK well describes several bulk properties SFG spectrum by molecular dynamics (MD) calculations. While MD simulation generally adopts short-range damping intermolecular interaction, it found that same procedure not adequate calculation transition dipole in strongly hydrogen bonding environment. Accordingly, improved...
When sum frequency generation (SFG) spectroscopy is applied to charged solid/liquid interfaces, the observed SFG signals include both second-order and third-order polarizations. The latter called χ(3) effect, which mainly includes induced molecular orientation by electric fields at interfaces. We theoretically evaluate effect on of liquid water using dynamics (MD) simulations. MD simulations enable us definitely calculate susceptibility as a bulk property, thereby separating it from usual...
We performed ab initio molecular orbital (MO) calculations of the response kernel (∂Qa/∂Vb), which represents intramolecular charge polarization by external electrostatic field, on basis coupled perturbed Hartree−Fock equation. The kernels some organic molecules including pyrazine, pyrazinyl radical, acetone, and 2-hydroxypropyl radical were calculated along present formulation. results revealed that hydrogen abstraction pyrazine causes product to be remarkably deformable in partial...
With detailed experimental studies and hydrodynamics particle-in-cell simulations we investigate the role of prepulse in laser proton acceleration. The or pedestal (amplified spontaneous emission) can completely evaporate irradiated region a sufficiently thin foil; therefore, main part pulse interacts with an underdense plasma. multiparametric demonstrate that generates quasistatic magnetic field, which its turn produces long-lived charge separation electrostatic accelerating ions.
This article summarizes the computational analysis of vibrational sum frequency generation (SFG) spectroscopy with molecular dynamics simulation. The allows direct comparison experimental SFG spectra and microscopic interface structure obtained by simulation, thereby obviates empirical fitting procedures observed spectra. In theoretical formulation, frequency-dependent nonlinear susceptibility an is calculated in two ways, based on energy representation time-dependent representation....
We study an electric quadrupole contribution to sum frequency generation (SFG) at air∕liquid interfaces in electronically and vibrationally nonresonant condition. Heterodyne-detected electronic spectroscopy of reveals that χ((2)) (second-order nonlinear susceptibility) has a negative sign nearly the same value for all eight liquids studied. This result is rationalized on basis theoretical expressions with taken into account. It concluded background SFG predominantly due interfacial...
Microscopic mechanism of ion transport through water-oil interface was investigated with molecular dynamics simulation. The formation/breaking a water finger during the passage explicitly formulated in free energy surface. calculated 2D surface clearly revealed hidden barrier accompanied by finger. This elucidates retarded rate interfacial transfer.
To develop an efficient material for the cathode of lithium-oxygen (Li-O2) secondary battery, oxygen reduction and evolution reactions (ORR OER) on a well-defined graphene electrode have been investigated in typical organic solvent, dimethyl sulfoxide (DMSO). The adsorption desorption behaviors solvents surface were evaluated by intrinsically surface-selective vibrational spectroscopy sum frequency generation (SFG) during ORR OER. After initial depositing lithium peroxide (Li2O2) LiClO4/DMSO...
Heterodyne-detected vibrational sum frequency generation spectroscopy was applied to the water surface for measuring imaginary part of second-order nonlinear susceptibility (Im χ(2)) spectrum in bend region first time. The observed Im χ(2) shows an overall positive band around 1650 cm–1, contradicting former theoretical predictions. We further found that NaI aqueous solution exhibits even larger band, which is apparently contrary flip-flop orientation water. These unexpected observations are...
Photochemical reactions at the air–water interface can show remarkably different rates from those in bulk water. The present study elucidates reaction mechanism of phenol characteristic by combination molecular dynamics simulation and quantum chemical calculations excited states. We found that incomplete hydrogen bonding to affects states associated with conical intersection significantly reduces barrier, resulting distinctively facilitated rate comparison phase. indicates be substantially...
Vibrational energy relaxation of azide anion in water was investigated with molecular dynamics simulation. The Landau–Teller formula without the solute electronic polarization exceedingly underestimated rate antisymmetric stretching mode, and thus various mechanisms were comprehensively evaluated to elucidate fast relaxation. As a result, direct vibrational ground state intramolecular redistribution (IVR) symmetric mode have equally dominant contributions decay rate. Intramolecular charge...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolute-solvent interaction in nonpolar supercritical fluid: a clustering model and size distributionAkihiro. Morita Okitsugu. KajimotoCite this: J. Phys. Chem. 1990, 94, 16, 6420–6425Publication Date (Print):August 1, 1990Publication History Published online1 May 2002Published inissue 1 August 1990https://pubs.acs.org/doi/10.1021/j100379a048https://doi.org/10.1021/j100379a048research-articleACS PublicationsRequest reuse permissionsArticle...
The vibrational sum frequency generation (SFG) spectra of gas−liquid interfaces NaCl and NaI aqueous solutions are computed analyzed by molecular dynamics (MD) simulations using a flexible polarizable model. MD calculations have reproduced the experimental features SFG spectra, including observed perturbation on in contrast to little NaCl. Analysis nonlinear susceptibility revealed that intermolecular correlation has significant contribution vibrationally resonant amplitude, which largely...
The second-order nonlinear susceptibility, which is the source of sum frequency generation (SFG) spectrum, for vapor−water interface calculated by molecular dynamics simulation based on time correlation formula. susceptibility well reproduces that recent phase-sensitive SFG experiment (Ji et al. Phys. Rev. Lett. 2008, 100, 096102), including positive imaginary part in 3000−3200 cm−1 region, a controversial problem assignment. It found this induced intermolecular orientational at through...
Since the basal plane surface of ice was first observed by sum frequency generation, an extraordinarily intense band for hydrogen(H)-bonded OH stretching vibration has been a matter debate. We elucidate remarkable spectral feature quantum mechanics/molecular mechanics calculations. The H-bonded is originated mostly from "bilayer-stitching" modes few bilayers, through significant intermolecular charge transfer. mechanism enhanced signal sensitive to order tetrahedral structure, as transfer...