Shevchenko Y. The kinetics of nonadiabatic transitions in molecular systems with strong relaxation

The thesis deals with the study of quantum kinetics of nonadiabatic donor-acceptor electron transfer through a molecular bridge. The theory that allows to describe sequential as well as superexchange transfer pathways employing the closed set of parameters is proposed. For the bridges that consist of more than 4-6 units, it is shown that at room temperature a superexchange mechanism is superimposed by sequential one even at a very small bridge population. For systems with a regular bridge, the necessary and sufficient conditions at which the kinetics of electron transfer can be considered as a single-exponential one are obtained. Moreover, the conditions are obtained at which contributions to the electron transfer rate from the two mechanisms are independent. The experiments on the electron transfer rate distance dependence are explained. Two new mechanisms (direct and repeated) of superexchange two-electron transfer are proposed and the conditions at which one mechanism dominates over another one arespecified.