Reorganization Parameters of Electronic Transitions in Electronically Delocalized Systems. 1. Charge Transfer Reactions

Abstract

This paper addresses the problem of calculating the free energy surfaces of charge transfer (CT) reactions in electronically delocalized systems involving direct electronic overlap of the donor and acceptor units. The model includes two electronic states of the solute linearly coupled to a linearly responding solvent in both the diagonal and off-diagonal terms of the Hamiltonian matrix. The exact solution for the adiabatic free energy surfaces along the CT reaction coordinate is derived as a function of the reorganization parameters invariant to the extent of electron delocalization and the parameter of electron delocalization. For dipolar solutes, the latter is defined through adiabatic differential and transition dipoles measured by optical spectroscopy. The invariant reorganization energy is the real, observable reorganization energy determining the vertical transition energy, bandwidth, and the activation energy of self-exchange transitions. The Golden Rule expression for the ET rate constant is obtai...