THE FREE-ENERGY PROFILES FOR THE ELECTRON-TRANSFER REACTIONS CALCULATED FROM THE INTEGRAL-EQUATION METHOD OF LIQUIDS

A microscopic description of the free energy profile for the electron transfer reaction is presented based on the extended reference interac tion site method (ex-RISM) in the statistical mechanical theory of mol ecular liquids. We employed the scheme proposed by Marcus to character ize the non-equilibrium solvent polarizations at the intermediate stat es of the reaction. The method is applied to two models of electron ex change reactions where the redox pairs have valence charges of 1/2 + / 1/2- and 2 +/3 +, and to a model of a charge separation reaction. Due to the non-linear nature of the hypernetted chain (HNC) closure to sol ve the RISM equation, our method can shed light on the non-linearity o f the free energy profiles.