Solvent dynamical effects on nonadiabatic electron transfer reactions at low temperature

Abstract

The role of solvent dynamics on low temperature nonadiabatic electron transfer reactions is explored. The solvent degrees of freedom orthogonal to the nuclear motion reaction coordinate are represented by a frictional term. Thus, motion along the reaction coordinate is described by a damped quantum oscillator equation of motion. This equation of motion is used to construct the nonadiabatic electron transfer rate constant which describes long range electron transfer phenomena such as occurs in biological oxidation-reduction reactions. The frictional dynamics are correctly described even for temperatures lower than the characteristic frequencies of the reaction coordinate and the friction. We exhibit the effects that friction can have on the electron transfer rate from room temperature down to 4 K, and qualitatively compare with typical biological electron transfer data, as interpreted using the conventional zero friction theory.