title: Impact of Temperature and Non-Gaussian Statistics on Electron Transfer in Donor-Bridge-Acceptor Molecules.
abstract: A combination of experimental data and theoretical analysis provides evidence of a bell-shaped kinetics of electron transfer in the Arrhenius coordinates ln k vs 1/T. This kinetic law is a temperature analogue of the familiar Marcus bell-shaped dependence based on ln k vs the reaction free energy. These results were obtained for reactions of intramolecular charge shift between the donor and acceptor separated by a rigid spacer studied experimentally by Miller and co-workers. The non-Arrhenius kinetic law is a direct consequence of the solvent reorganization energy and reaction driving force changing approximately as hyperbolic functions with temperature. The reorganization energy decreases and the driving force increases when temperature is increased. The point of equality between them marks the maximum of the activationless reaction rate. Reaching the consistency between the kinetic and thermodynamic experimental data requires the non-Gaussian statistics of the donor-acceptor energy gap described by the Q-model of electron transfer. The theoretical formalism combines the vibrational envelope of quantum vibronic transitions with the Q-model describing the classical component of the Franck-Condon factor and a microscopic solvation model of the solvent reorganization energy and the reaction free energy.
authors.affiliation: School of Molecular Sciences, Arizona State University , P.O. Box 871604, Tempe, Arizona 85287-1604, United States.
authors.forename: Morteza M
authors.initials: MM
authors.lastname: Waskasi
authors.affiliation: Chemistry Department, Brookhaven National Laboratory , Box 5000, Upton, New York 11973-5000, United States.
authors.forename: Marshall D
authors.initials: MD
authors.lastname: Newton
authors.affiliation: School of Molecular Sciences, Arizona State University , P.O. Box 871604, Tempe, Arizona 85287-1604, United States.|Department of Physics, Arizona State University , P.O. Box 871504, Tempe, Arizona 85287-1504, United States.
authors.forename: Dmitry V
authors.identifier: 0000-0002-9352-764X
authors.initials: DV
authors.lastname: Matyushov