Two aspects of ultrafast photodynamics: molecular photo-ionization and coherent control of molecular fragmentation and photoreactions involving conical intersections

摘要

The paper focuses on tow topics of ultrafast photodynamics. The first deals with the ionization and fragmentation of molecules using intense femtosecond laser pulses, while the second addresses ultrafast reaction dynamics of medium-sized organic molecules involving conical intersections. In particular, the dynamics of the photo-initiated unimolecular electrocyclic ring-opening reactions of 1,3,5-cyclooctatriene and 7-dehydrocholesterol are examined in a femotosecond pump-probe experiment in the gas phase using photo-ionization in combination with time-of-flight mass spectrometry for detection. Particular care is taken in the experiment to establish well-defined conditions and, especially, to shed light on the probe step. This is exemplified by the similar-sized molecule toluene, exploring several fundamental aspects of its ionition and fragmentation behaviour.