Characterization of low-lying ungerade Rydberg and valence states in molecular chlorine by REMPI-PES

Abstract

The study of molecular reactions in the gas phase, initiated by the absorption of light in the visible, ultraviolet (UV) and vacuum ultraviolet (VUV) is an attractive field of research in chemical physics. Much of our present understanding derives from ingenious state-resolved experiments and detailed calculations on elementary photochemical reactions. The investigations involve a preparation of specific states of the reagents and characterization of the products in order to learn about geometrical and orientational effects, state distributions resulting from many different reaction pathways and the competition between reactive and inelastic channels. An exciting prospect is to drive chemical reactions in new and selective ways by optical excitation of the transition state in the course of the reaction. The study of diatomic molecules provides rich testing ground and detailed spectroscopic knowledge on the valence electronic structure of these molecules is a prerequisite. Photoionization, particularly in combination with advanced laser techniques, continues to be an attractive method to obtain some of this information. In the present study, resonance enhanced multiphoton ionization with kinetic energy resolved electron detection is reported for molecular chlorine. Molecular excited states of Rydberg and valence character have been studied between 73,000 and 79,000 cm⁻¹.