Low-Temperature Fluorescence Spectra and Crystal Field Splittings of Rare-Earth Activated SrS Phosphors

As a continuation of an earlier work, SrS phosphors, singly activated with rare-earth ions have been excited with uv irradiation, at 77°K. The resultant visible fluorescent emissions have been measured and correlated with crystal field splittings of energy levels. Energy level diagrams are presented with possible term assignments. Where possible, comments are made about the symmetry of the activator sites.