PNNL

Abstract

The reorganization energy is an important quantity controlling electron transfer rates. The internal contribution arising from the energy to reorganize donor/acceptor bonds can be evaluated by the ‘direct’ and ‘4-point’ methods. We examine how spatial separation leading to the non-interacting character of the donor and acceptor affects the reorganization energy. We show that the direct method captures contributions from interaction of the donor and acceptor while the 4-point method does not, and the two methods converge at large separation. Comparing reorganization energies determined by the two methods yields a measure of the degree of interaction between the initial and final states. The analysis is illustrated in the characterization of small polarons in iron oxides.