Kinetics of electron transfer reaction between manganate and permanganate ions. Calculation of rate constant and activation energy

Abstract

The rate constant and activation energy of the electron transfer reaction in a polar medium, between MnO^–₄ and MnO^2–₄ ions, are calculated in terms of the theory of nonadiabatic transitions. The dependence of the matrix element V_if, determining the probability of the electron transition in the intersystem crossing point, on the distance between the ions is investigated. The exponential factor of the rate constant involves the contributions due to the solvent reorganization, the deformation of metal–ligand bonds and the work term. The change of the rate constant dependant on the distance between the ions is considered. Agreement between the calculated and experimental activation energy becomes better if the dependence of the temperature coefficient of the static permittivity on the ionic strength is taken into account.