2002 Fiscal Year Final Research Report Summary
Statistical physics of liquids an solution
| Project/Area Number |
12640378
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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 |
物性一般(含基礎論)
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
YOSHIMORI Akira Department of physics, Ass. Prof., 大学院・理学研究院, 助教授 (90260588)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Time-dependent density functional / interaction site models / solvation dynamics / nonlinear effects of density fields / trapping diffusion model / glass transition / specific heat in nonequilibrium systems / hard sphere system |
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| Research Abstract |
1. The extension of time-dependent density functional methods to molecular liquids.
Time-dependent density functional methods were extended to interaction site models, employed in computer simulations of molecular liquids. One can calculate density fields of interaction sites if one has free energy functional of interaction site density fields. Many equilibrium theories, such as RISM, can give the free energy functionals.
2. Dynamics of distribution widths in solvation.
Nishiyama and Okada have recently found that time-dependent fluorescence spectral widths relax more slowly than peaks in solvation dynamics. Previous theories cannot explain their results because the relaxation rates of the peak and width are exactly the same in the theories. To understand the phenomena, a simple model was considered where nonlinear effects of density fields were included as well as the rotational relaxation of molecules. The dynamics of distribution widths was calculated using the model. The results show that the relaxation of widths is slower than that of peaks if the density field relaxes slowly enough. We are calculating molecular dynamics simulations to confirm the model at the present.
3. Studies of supercooled liquids and the glass transition
(1) The trapping diffusion model was derived from microscopic viewpoints. The jump rate distribution was microscopically derived using the chemical reaction theory. The results show that the jump rate is distributed when particles have some motions with different relaxation rates. In addition, an explicit expression of the distribution was obtained. In the small rate region, the distribution was a power law.
(2) Specific heats in the glass transition were studied. To explain a drastic change in specific heats, some models were calculated using a new definition of a nonequilibrium specific heat.
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