このエントリーをはてなブックマークに追加
ID 57460
FullText URL
Author
Sumi, Tomonari Department of Chemistry, Faculty of Science, Okayama University ORCID Kakenhi publons
Maruyama, Yutaka Co-Design Team, Exascale Computing Project, RIKEN Advanced Institute for Computational Science
Mitsutake, Ayori Co-Design Team, Exascale Computing Project, RIKEN Advanced Institute for Computational Science
Koga, Kenichiro Department of Chemistry, Faculty of Science, Okayama University ORCID Kakenhi
Abstract
In the conventional classical density functional theory (DFT) for simple fluids, an ideal gas is usually chosen as the reference system because there is a one-to-one correspondence between the external field and the density distribution function, and the exact intrinsic free-energy functional is available for the ideal gas. In this case, the second-order density functional Taylor series expansion of the excess intrinsic free-energy functional provides the hypernetted-chain (HNC) approximation. Recently, it has been shown that the HNC approximation significantly overestimates the solvation free energy (SFE) for an infinitely dilute Lennard-Jones (LJ) solution, especially when the solute particles are several times larger than the solvent particles [T. Miyata and J. Thapa, Chem. Phys. Lett. 604, 122 (2014)]. In the present study, we propose a reference-modified density functional theory as a systematic approach to improve the SFE functional as well as the pair distribution functions. The second-order density functional Taylor series expansion for the excess part of the intrinsic free-energy functional in which a hard-sphere fluid is introduced as the reference system instead of an ideal gas is applied to the LJ pure and infinitely dilute solution systems and is proved to remarkably improve the drawbacks of the HNC approximation. Furthermore, the third-order density functional expansion approximation in which a factorization approximation is applied to the triplet direct correlation function is examined for the LJ systems. We also show that the third-order contribution can yield further refinements for both the pair distribution function and the excess chemical potential for the pure LJ liquids.
Published Date
2016-06-10
Publication Title
Journal of Chemical Physics
Volume
volume144
Issue
issue22
Publisher
American Institute of Physics
Start Page
224104
ISSN
00219606
NCID
AA00694991
Content Type
Journal Article
language
英語
OAI-PMH Set
岡山大学
File Version
author
PubMed ID
DOI
Web of Science KeyUT
Related Url
isVersionOf https://doi.org/10.1063/1.4953191
Funder Name
Ministry of Education, Culture, Sports, Science and Technology