The Distances of the Closest Approach and of the Reaction Site-From the Electrode-for Adiabatic Heterogeneous Electron Transfer. The Case of Pyridinium (Mono) Cations

Abstract

In investigating the heterogeneous electron transfer process in some pyridinium compounds, those physical (distance) parameters were investigated which could be relevant to the adiabaticity of a heterogeneous electron transfer process. These distance parameters are: the closest approach, the position of the interfacial potential-energy barrier maximum and the reaction site. The pyridinium (mono) cations were treated as charged Shard) sphere with the reaction site at the center of the sphere. With this assumption the distance of the closest approach and the distance of the-reaction-site - from the electrode surface - were investigated under the constraint Kel (electronic transmission coefficient) = 1. Various models were considered and the Khan model was found to be quite sound, versatile as well as convenient to use. Results of these calculations are presented the reaction site as calculated through Khan model came close to the sum of radii of the solvent and the pyridinium cations under study.