Spectra and dynamics of calcium monochloride

Abstract

The alkaline earth monohalides (MX) represent an ideal molecule for studying molecular Rydberg states, as they are well described as by an ion-core containing two closed shell atomic ions (M2+,X-) and an unpaired electron. The spectra and dynamics of Rydberg states allows the testing of theories of electronic structure and nuclear-electronic energy exchange. This thesis presents the results of a series of experimental studies on the least well-studied MX molecule, CaCl (calcium monochloride). The majority of these investigations were conducted in a specialized molecular beam apparatus described in some detail. The spectroscopy of CaCl is challenging because of the onset of predissociation at n* [approx.] 3. The reduction in ionization quantum yield associated with the predissociation greatly reduces our ability to record Rydberg state spectra, but provides opportunities to model the predissociation processes with the results of observed states. Such a model was accomplished with the 2[Sigma]+ repulsive state via a linewidth analysis, and with the 2[Pi] state with a qualitative model. The experiments described here represent a significant step to understanding the dynamics of MX Rydberg states from a frequency-domain perspective, and should allow the development of future studies to completely characterize the predissociative processes in CaCl.