Free energies of electron transfer reactions in polarizable, nondipolar, quadrupolar solvents

A continuum theory is developed for describing the influence of polarizable , nondipolar, quadrupolar solvents on charge-transfer processes. The fluctu ating configuration of solvent quadrupole moments and associated nonequilib rium free energy are described in terms of multidimensional solvent coordin ates. The solvent reorganization free energy is obtained in the framework o f both one- and two-sphere cavity descriptions of the reaction systems. As an application, electron transfer for bridged donor-acceptor systems in ben zene is considered. It is found that the continuum theory predictions for o uter-sphere reorganization foe energy are in good accord with both experime ntal estimates and molecular-level theory results.