title: A solvation-free-energy functional: a reference-modified density functional formulation.
abstract: The three-dimensional reference interaction site model (3D-RISM) theory, which is one of the most applicable integral equation theories for molecular liquids, overestimates the absolute values of solvation-free-energy (SFE) for large solute molecules in water. To improve the free-energy density functional for the SFE of solute molecules, we propose a reference-modified density functional theory (RMDFT) that is a general theoretical approach to construct the free-energy density functional systematically. In the RMDFT formulation, hard-sphere (HS) fluids are introduced as the reference system instead of an ideal polyatomic molecular gas, which has been regarded as the appropriate reference system of the interaction-site-model density functional theory for polyatomic molecular fluids. We show that using RMDFT with a reference HS system can significantly improve the absolute values of the SFE for a set of neutral amino acid side-chain analogues as well as for 504 small organic molecules.
authors.affiliation: Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan.
authors.forename: Tomonari
authors.initials: T
authors.lastname: Sumi
authors.affiliation: Department of Physics, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan.|JST, PREST, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan.
authors.forename: Ayori
authors.initials: A
authors.lastname: Mitsutake
authors.affiliation: Department of Physics, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Maruyama
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D009842:Oligopeptides / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D011789:Quantum Theory; D012995:Solubility; D013816:Thermodynamics
chemical_list: D000596:Amino Acids; D009842:Oligopeptides; D009930:Organic Chemicals; C506175:chignolin
keywords: 3D-RISM theory; amino acid side-chain; chignolin; classical density functional theory; salvation-free-energy; water