Assessment of free energy expressions in RISM integral equation theory: theoretical prediction of partition coefficients revisited

We assess the performance of free energy expressions so far available in the reference interaction site model (RISM) integral equation theory. Free energies of solvation in aqueous and chloroform solutions along with the partition coefficients of them are calculated for 16 organic molecules. Static polarity effects are included using hybrid RISM and Hartree-Fock methods. Our best estimates are obtained from the expression of the distributed partial wave expansion that leads to the standard deviations less than 1.3 kcal mol(-1) and 1.1 in the solvation free energies and partition coefficients, respectively.