Theoretical Studies of Resonantly Enhanced Multiphoton Ionization Processes in Molecules

Abstract

Multiphoton absorption and ionization processes add a new dimension to the study of excited state dynamics in atomic and molecular systems. The extreme energy- and state-selectivity achieved through the use of lasers enables one to access specific excited states which would otherwise be inaccessible in single photon spectroscopy due to the lack of appropriate light sources or due to dipole selection rules. Photoionization out of these excited states combined with photoelectron energy analysis yields detailed information about the excited state and the ionization continuum. Recent experiments [1–14] on multiphoton ionization of diatomic molecules H₂, N₂, NO and CO have revealed several interesting features, such as the state selectivity in the residual ion, non-Franck-Condon behavior, Rydberg-valence mixing, rotational and vibrational state dependence of photoelectron angular distributions, and vibrational and rotational autoionization. Multiphoton ionization has also been used to study van der Waal’s complexes of rare gas atoms [15].

Contribution No. 7106