A simple solvent model for electron transfer reactions.

An application of the polarizable continuum solvent model to the Fe²⁺/Fe³⁺ electron exchange reaction in water is presented. The model accounts for the internal energy of the ions, and the electrostatic and repulsion terms of the solute-solvent interaction. By describing all the solvent motions with only two geometrical parameters, one finds an activation energy in good agreement with experimental values; the model provides a simple and coherent description of the diffusion and activation steps of the reaction, and a way of directly calculating a quantity that appears in the expression of electronic transmission factor.