Thermochemistry of solvation: A self-consistent three-dimensional reference interaction site model approach

We developed a self-consistent three-dimensional reference interaction site model integral equation theory with the molecular hypernetted chain closur e (SC-3D-RISM/HNC) for studying thermochemistry of solvation of ionic solut es in a polar molecular solvent. It is free from the inconsistency in the p ositions of the ion-solvent site distribution peaks, peculiar to the conven tional RISM/HNC approach and improves the predictions for the solvation the rmodynamics. The SC-3D-RISM treatment can be readily generalized to the cas e of finite ionic concentrations, including the consistent dielectric corre ctions to provide a consistent description of the dielectric properties of ion-molecular solution. The proposed theory is tested for hydration of the Na+ and Cl- ions in ambient water at infinite dilution. An improved agreeme nt of the ion hydration structure and thermodynamics with molecular simulat ion results is found as compared to the conventional RISM/HNC treatment. (C ) 2000 American Institute of Physics. [S0021-9606(00)51941-2].