Quantum dynamical simulations of ultrafast photoinduced electron-transfer processes

Multilevel Redfield theory is employed for the modeling of ultrafast electron-transfer (ET) reactions in polyatomic systems, exhibiting coherent wave-packet motion in excited and/or ground electronic states. Two-electronic-state models are constructed for excited-state ET driven by coherent vibrational motion in the initially excited donor state and characteristic features of ET dynamics in normal and inverted regions are outlined. Three-electronic-state models focus on the mechanisms of coherent repopulation of the electronic ground state, which may accompany ultrafast photoinduced ET. It is shown that wave-packet motion in the electronic ground state may be initialized not only by the laser excitation, but also by the reaction itself. Employing the numerically exact so-called self-consistent hybrid method, the validity of Redfield theory is critically examined. (C) 2004 Elsevier B.V. All rights reserved.