Time-resolved photoelectron spectroscopy: Non-adiabatic dynamics in polyatomic molecules

Femtosecond time-resolved photoelectron spectroscopy is emerging as an important technique for investigating photodynamics in polyatomic molecules. Photoelectron spectroscopy is sensitive to both electronic configurations and vibrational dynamics and is therefore well suited to the study of ultrafast non-adiabatic processes. We emphasize the conceptual interpretation of wavepacket dynamics experiments, particularly stressing the critical role of the final state. We discuss the advantages of the molecular ionization continuum as the final state in polyatomic wavepacket experiments and show how the electronic structure of the continuum can be used to help to disentangle electronic from vibrational dynamics. We illustrate these methods with examples from internal conversion in polyenes and polyaromatic hydrocarbons, electronic relaxation in substituted benzenes, excited state intramolecular proton transfer, azobenzene photoiosomerization dynamics and non-adiabatic photodissociation dynamics.