Quantum Theory of Electron‐Transfer Processes in Solution

A theory of electron transfer processes in solution, including electrode reactions, is presented which rests on a general quantum‐mechanical formulation of chemical kinetics. The familiar harmonic oscillator model is used to account for the role of the polar solvent in the electron transfer. An independent evaluation of the probabilities of electron and nuclear transitions permits to avoid the limitations of previous classical (or semiclassical) theories and that of quantum‐mechanical treatments based on perturbation theory as well. In this way the whole intermediate region between the limits of adiabatic and nonadiabatic processes is included and nuclear tunneling at any temperature is taken into account. The main results of earlier theories are obtained as special cases in the frame of the present treatment.