Collective treatment of inner sphere reactions. Part 2.—Contributions from the ionic solvation surface

Abstract

Molecular giant resonance and solvation sphere surface modes of oscillation were introduced and applied to the electron transfer reaction in two previous papers. The giant resonances are associated with relative ion-solvent motions in the first solvation sphere, and these degrees of freedom enter into the activation for the electron transfer transition. In this paper a similar analysis is applied to the surface modes. Surface oscillations are important. They provide a measure of the interaction between the solvated ion and the medium neighbouring it. We find that it is unlikely that surface reorganization plays any significant role in an outer sphere reaction. On the other hand, for the inner sphere reaction, for which gross chemical change takes place, these reorganization energy contributions can be significant. Several examples are considered.