Calculation of the energy of repolarization for a ‘soft-charge’ electron-transfer transition

Abstract

The problem of the calculation of the energy needed to repolarize the dielectric environment during an electron-transfer reaction is considered. Particular attention is paid to the case in which one of the species of the reaction involves only an electrically neutral (and perhaps non-polar) species. The method of calculation makes use of interpenetrating charge distributions. Such systems of charge, as models for solvated monatomic ions, were introduced several years ago. A simple modification amends this type of model to treat the neutral species. The energy to repolarize the dielectric environment, which is an essential quantity in the energy of activation for the electron-transfer reaction, depends upon the ionic radius as well as a core and effective Bohr radius for the electron in the neutral species. The model is applied to the case of the reduction of a simple monatomic cation to form a solvated atomic species. The particular example considered here, for reference, is that of the reduction of lithium in the process of the electrodeposition of that species.