Vibronic and Coherent Effects on Interfacial Electron Transfer Dynamics

This Letter examines fundamental issues for electron transfer (ET) dynamics, such as adiabatic versus nonadiabatic effects during interfacial ET, the influence of vibrational degrees of freedom on the electronic dynamics, the occurrence of electronic coherences and the ensuing dephasing effects. The interplay of these mechanisms during the ultrafast ET is discussed. A theoretical method for the quantum dynamics of electrons in flexible molecular systems is used to study such issues on the interfacial ET from the perylene chromophore to the TiO2 semiconductor surface. By analyzing the Fourier transform of the survival probability curves, it is possible to discern the oscillating features that are caused by electronic coherences and vibronic effects. The vibronic degrees of freedom are treated within the atomistic level of description and their effects identified on the charge transfer dynamics. The insights revealed are general and thus can be useful for the analysis of other ET phenomena.