Nonequilibrium free-energy profile of charge-transfer reaction in polarizable solvent studied using solvent-polarizable three-dimensional reference interaction-site model theory

The effects of the electronic polarization of solvent on the nonequilibrium free-energy profiles of charge-transfer reactions were studied using integral equation theory. Employing the solvent-polarizable three-dimensional reference interaction-site model theory, recently proposed by us, we first present a theoretical formalism that gives the free-energy profile in polarizable solvents. We then perform numerical calculations on three model systems. We demonstrate that electronic polarization of the solvent alters the solvent reorganization energy in two different ways. The first is the reorganization of the equilibrium solvation structure through the modification of the solute-solvent interaction, and the second is the stabilization of the nonequilibrium solvent fluctuation through the electronic polarization. The former increases, whereas the latter decreases the reorganization energy. In our model calculations, the solvent reorganization energy is reduced because the latter makes a larger contribution than does the former.