Ab initio study of inner-sphere reorganization energy for diatomic molecules in gas-phase electron transfer processes

Abstract

On the basis of the improved self-exchange model of reorganization phenomenon and accurate potential functions, several scaling methods of inner-sphere reorganization energy (RE) of diatomic molecules in gas-phase electron transfer processes are presented in this paper, the structural reorganization index is given, and the parameters involved are determined via ab initio calculation at the Hartree-Fock self-consistent field level (HF-SCF/6-31G ∗). The results indicate that ab initio results give good agreement with experiment for the inner-sphere RE and the potential constants ( r e , D e , f, g) of reactant molecules, and that the Hartree-Fock method is an accurate and reliable method for analyzing the reorganization effects in gas-phase electron transfer processes. The estimated errors for inner-sphere RE are within ±500 cm −1 (±1.5 kcal mol −1) or less, and are due to the limited basis sets within the HF-SCF method. It should be emphasized that, for gas-phase electron transfer processes, it is essential to calculate accurately the inner-sphere RE, while the outer-sphere effect may be neglected.