Polyatomic molecules in condensed phase: Bond order index and solvation energy studied by RISM-SCF theory

Abstract

The reference interaction site model - self-consistent field (RISM-SCF) theory was applied to a series of polyatomic molecules in aqueous solution, including CH4, NH3, H2O and HF. The bond order index, which characterizes the chemical bond, and its change by the solvation were studied by comparison with a dielectric continuum model. The change in the electronic structure was also associated with the solvation free energy. We find that the bond order indexes are not sensitive to the solvation effect even if the charge assigned to the atom is considerably changed. The distortion in the electronic energy is in proportion to the change in the solvation energy, showing that the linear response regime is a good expression of the solvation process examined here, in spite of solving the non-linear RISM-SCF equation. © H.Sato, D.Yokogawa, S.Sakaki.