EFFECT OF ENVIRONMENT ON SUPEREXCHANGE ELECTRON TRANSFER IN A MULTIPLE BRIDGED DONOR-ACCEPTOR SYSTEM

Electron transfer dynamics in donor-bridge-acceptor (DBA) systems under dissipative environment is investigated by using the quasi-adiabatic propagator path integral approach. The dephasing and relaxation rates are extracted from the Fourier transform of the time-dependent population difference of the donor and the acceptor states. Comparing the rates obtained from the DBA and the effective two state systems, respectively, we reveal the validity of the superexchange mechanism. It is found that the coupling of the environment to the bridges does not affect the superexchange rates for the bridges having high enough electronic energies, and the superexchange mechanism still works quite well even though the population on the bridges is over than 0.2 in a tested system.