| Project/Area Number |
13640509
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
MATUBAYASI Nobuyuki Institute for Chemical Research, Instructor, 化学研究所, 助手 (20281107)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2001: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Keywords | energy representation / distribution function / chemical potential / solvation free energy / solute-solvent interaction / computer simulation / hydrophobicity / supercritical fluid / 水溶液 |
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| Research Abstract |
The energy representation of the molecular configuration in a dilute solution is introduced to express the solvent distribution around the solute over a one-dimensional coordinate specifying the solute-solvent interaction energy. In this representation, the correspondence is shown to be one-to-one between the set of solute-solvent interaction potentials and the set of distribution functions On the basis of the one-to-one correspondence, an approximate functional for the chemical potential of a solute in solution is constructed by adopting the Percus-Yevick-like approximation in the repulsive region of the solute-solvent interaction and the hypernetted-chain-like approximation in the attractive region. The chemical potential is then given exactly to second order with respect to the solvent density and to the solute-solvent interaction. It is demonstrated that the chemical potentials of nonpolar, polar, and ionic solutes in water are evaluated accurately and efficiently from the single functional over a wide range of thermodynamic conditions. Furthermore, the conformation of a nanoscale molecule such as protein varies strongly in response to solute-solvent interactions. An approach to the solvation free energy of a solute molecule with conformational flexibility thus needs to be established toward treating a solution system of functional importance. The method of energy representaion is extended to treat the solvation free energy of a flexible solute molecule, In this work, we examined solute systems in water with stretching and/or torsioal degrees of freedom for intramolecular motion, and demonstrated the performance of the method over a wide range of thermodynamic conditions including both ambient and supercritical. The aggregation behaviors of hydrophobic and hydrophilic solutes in water are also treated within the same framework.
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