The potential of mean force between polyatomic molecules in polar molecular solvents

Theoretical results obtained with the extended reference interaction site (XRISM) formalism are presented for site-site solute solvent correlations and solute-solute potentials of mean force for infinitely dilute polar molecular solutes in various polar solvents. The standard RISM site-site Ornstein-Zernike like equations, in a Coulomb renormalized form, with a hypernetted chain (HNC) analog closure are used to derive results for polar molecular solutes in polar molecular solvents. For a dipolar diatomic solute the difference in the solvation behavior between atomic and molecular solvents is examined. Finite concentration results are compared with the infinite dilution intermolecular site-site potentials of mean force for diatomic molecules in a simple fluid solvent.