Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)  

We present a combination of three-dimensional
reference interaction site model self-consistent field (3D-RISM-
SCF) theory and the variational quantum eigensolver (VQE) to
consider the solvent distribution effects within the framework of
quantum-classical hybrid computing. The present method, 3D-
RISM-VQE, does not include any statistical errors from the solvent
configuration sampling owing to the analytical treatment of the
statistical solvent distribution. We apply 3D-RISM-VQE to
compute the spatial distribution functions of solvent water around
a water molecule, the potential and Helmholtz energy curves of
NaCl, and to analyze the Helmholtz energy component and related
properties of H2O and NH+4. Moreover, we utilize 3D-RISM-VQE
to analyze the extent to which solvent effects alter the efficiency of quantum calculations compared with calculations in the gas phase using the L1-norms of molecular electronic Hamiltonians. Our results demonstrate that the efficiency of quantum chemical calculations on a quantum computer in solution is virtually the same as that in the gas phase.

DOI： 10.1021/acs.jctc.3c01189

Authorship：Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/5.0185157

Authorship：Corresponding author  

DOI： 10.1093/chemle/upad009

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.molliq.2023.122503

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/5.0159130

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1063/5.0158046

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.molliq.2023.122503

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.molliq.2023.122418

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.molliq.2023.122311

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1021/acs.jpcb.3c00343

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1063/5.0142256

Language：English  

DOI： 10.1002/jcc.27009

Web of Science

PubMed

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1088/1757-899X/1280/1/012002

Language：English   Publisher：Journal of Chemical Physics  

A theoretical method for calculating the thermodynamic properties and phase equilibria of liquid-liquid mixtures using the integral equation theory is proposed. The solvation chemical potentials of the two components are evaluated by the integral equation theory and the isothermal-isobaric variation of the total density with composition is determined to satisfy the Gibbs-Duhem relation. Given the density of a pure component, the method can calculate the densities of the mixture at any composition. Furthermore, it can treat the phase equilibrium without thermodynamic inconsistency with respect to the Gibbs-Duhem relation. This method was combined with the reference interaction-site model integral equation theory and applied to mixtures of water + 1-alcohol by changing the alcohol from methanol to 1-butanol. The destabilization of the mixing Gibbs energy by increasing the hydrophobicity of the alcohol and demixing of the water-butanol mixture were reproduced. However, quantitative agreement with experiments is not satisfactory, and further improvements of the integral equation theory and the molecular models are required.

DOI： 10.1063/5.0131475

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Scopus

PubMed

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acs.jcim.2c00192

PubMed

Publishing type：Research paper (scientific journal)   Publisher：Cold Spring Harbor Laboratory  

DOI： 10.1101/2022.02.08.479071

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：{MDPI} {AG}  

<jats:p>The protonation/deprotonation reaction is one of the most fundamental processes in solutions and biological systems. Compounds with dissociative functional groups change their charge states by protonation/deprotonation. This change not only significantly alters the physical properties of a compound itself, but also has a profound effect on the surrounding molecules. In this paper, we review our recent developments of the methods for predicting the Ka, the equilibrium constant for protonation reactions or acid dissociation reactions. The pKa, which is a logarithm of Ka, is proportional to the reaction Gibbs energy of the protonation reaction, and the reaction free energy can be determined by electronic structure calculations with solvation models. The charge of the compound changes before and after protonation; therefore, the solvent effect plays an important role in determining the reaction Gibbs energy. Here, we review two solvation models: the continuum model, and the integral equation theory of molecular liquids. Furthermore, the reaction Gibbs energy calculations for the protonation reactions require special attention to the handling of dissociated protons. An efficient method for handling the free energy of dissociated protons will also be reviewed.</jats:p>

DOI： 10.3390/j4040058

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Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Water in the supercritical region of the phase diagram exhibits a markedly different structure and properties from that at ambient conditions, which is useful in controlling chemical reactions. Nonetheless, the experimental, as well as theoretical, characterization of the substance is not easy because the region is next to the critical point. This article reviews the experimental as well as theoretical studies on water in the supercritical region and its properties as a solvent for chemical reactions, as carried out by the authors and based on small-angle X-ray scattering and the statistical mechanics theory of molecular liquids, also known as reference interaction-site model (RISM) theory.

DOI： 10.3390/j4040049

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry ({RSC})  

DOI： 10.1039/d1nj02015c

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry ({RSC})  

DOI： 10.1039/d1sm00152c

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PubMed

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

A computational method to investigate the global conformational change of a protein is proposed by combining the linear response path following (LRPF) method and three-dimensional reference interaction site model (3D-RISM) theory, which is referred to as the LRPF/3D-RISM method. The proposed method makes it possible to efficiently simulate protein conformational changes caused by either solutions of varying concentrations or the presence of cosolvent species by taking advantage of the LRPF and 3D-RISM. The proposed method is applied to the urea-induced denaturation of ubiquitin. The LRPF/3D-RISM trajectories successfully simulate the early stage of the denaturation process within the simulation time of 300 ns, whereas no significant structural change is observed even in the 1 mu s standard MD simulation. The obtained LRPF/3D-RISM trajectories reproduce the mechanism of the urea denaturation of ubiquitin reported in previous studies, and demonstrate the high efficiency of the method.

DOI： 10.1002/jcc.26481

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PubMed

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/jcc.26502

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/5.0036289

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PubMed

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/molecules26020271

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PubMed

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Event date： 2024.6

Language：English   Presentation type：Oral presentation (invited, special)  

Country：Kazakhstan  

Event date： 2024.1

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：岡崎コンファレンスセンター, 岡崎市   Country：Japan  

Event date： 2024.1

Language：English   Presentation type：Oral presentation (general)  

Venue：Ah Haa School for the Arts, Telluride   Country：United States  

Event date： 2023.12

Language：English   Presentation type：Oral presentation (keynote)  

Venue：Maruay Garden hotel, Bangkok   Country：Thailand  

Event date： 2023.11

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：名古屋国際会議場, 名古屋市   Country：Japan  

Event date： 2023.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Boston University   Country：United States  

Event date： 2023.9

Language：English   Presentation type：Oral presentation (invited, special)  

Country：Japan  

Event date： 2023.9

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：九州工業大学戸畑キャンパス   Country：Japan  

Event date： 2023.7

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Patthaya   Country：Thailand  

Event date： 2023.7

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：名古屋国際会議場   Country：Japan  

Event date： 2023.3

Language：English   Presentation type：Oral presentation (invited, special)  

Event date： 2023.2

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Quy Nhon   Country：Viet Nam  

Event date： 2022.12

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：The Emerald Hotel, Bangkok   Country：Thailand  

Event date： 2022.11

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：The Magellan Sutera Resort, Sabah   Country：Malaysia  

Event date： 2022.9

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2022.9

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Korea Institute for Advanced Study, Seoul   Country：Korea, Republic of  

Event date： 2022.7

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Country：Japan  

Event date： 2022.7

Language：English   Presentation type：Oral presentation (invited, special)  

Country：Canada  

Event date： 2022.6

Language：English   Presentation type：Oral presentation (invited, special)  

Country：Thailand  

Event date： 2022.6

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：つくば国際会議場  

Event date： 2022.6

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Event date： 2022.2

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：the International Centre for Interdisciplinary Science and Education (ICISE), Quy Nhon   Country：Viet Nam