Nonadiabatic Molecular Dynamics Simulation of Light-Induced Electron Transfer from an Anchored Molecular Electron Donor to a Semiconductor Acceptor †

A nonadiabatic molecular dynamics (MD) simulation of the photoinduced electron transfer (ET) from a molecular electron donor to the TiO2 acceptor is reported. The system under study is typical of the dye sensitized semiconductor nanomaterials used in solar cell, photocatalysis, and photoelectrolysis applications. The electronic structure of the dye−semiconductor system and the adiabatic dynamics are simulated by ab initio MD, whereas the nonadiabatic effects are incorporated by the quantum-classical mean-field approach. A novel procedure separating the nonadiabatic and adiabatic ET pathways is proposed. The simulation provides a detailed picture of the ET process. For the specific system under study, ET occurs on a 30 fs time scale, in agreement with the ultrafast experimental data. Both adiabatic and nonadiabatic pathways for the ET are observed. The nonadiabatic transfer entirely dominates at short times and can occur due to strong localized avoided crossing as well as extended regions of weaker nonadia...