Knowledge Bank

Resonance enhanced multiphoton ionization (REMPI) coupled with high-resolution photoelectron spectroscopy is an important state-specific probe of the photoionization dynamics of molecular excited states. In this talk we will discuss results of studies of ion rotational and vibrational distributions for REMPI of several small molecules such as $H2,O2,NO,CH$, and OH. Some highlights of these results include (i) non-Franck-Condon ion vibrational distributions arising from the presence of autoionizing $(H2)$ and shape resonances $(O2)$ and from orbital evolution in the resonant state (OH), and (ii) rotational distributions of ions and the associated photoelectron angular distributions (NO and CH) with emphasis on their non-atomic-like behavior.