Activationless dynamic solvent effect

The dynamic solvent effect (DSE) is studied numerically at any free energy of electron transfer. In the activationless case the exact result known for an irreversible transfer is confirmed but the commonly accepted approximate results for reversible transfer were corrected. The general rate dependence on electron coupling is shown to fit the Zusman interpolation between the perturbation theory and DSE, not only in the normal and inverted region but in the activationless case as well. DSE is responsible for the saturation of the electron transfer at short distances where the electron coupling becomes strong.