Abstract : This report describes a theoretical and experimental investigation of the rare gas monohalides. As a class, these molecules show great promise for achieving high power acalable laser action in the near UV portion of the spectrum. A theory has been developed to describe the structure of these molecules. The predictions of this theory are borne out by fluorescence experiments carried out in high pressure rare gas/halogen mixtures, using electron-beam excitation. The kinetics of these mixtures and their potential as high power lasers are discussed.