Analytical approach to molecular liquids. IV: Solvation dynamics and electron-transfer reactions

The solvation dynamics of a pair of ions rigidly held a fixed distance from each other in either a dipolar hard-sphere solvent or a dipolar dumbbell solvent is investigated under the mean spherical approximation (MSA) applied to an interaction-site model in which the pair of ions is treated as a rigid extended dipolar dumbbell. An analytical expression for the reorganization free energy for a charge transfer reaction is obtained and compared with numerical results obtained via a thermodynamic cycle. Solvent effects on the rate of a charge transfer reaction are also investigated using the dielectric Green-function theory developed by Newton and Friedman.