Summary
In the cadmium sulfide crystals an easily observed and measured phenomenon is the low temperature bound exciton emission spectrum. The purpose of this work was to establish a relationship between the bound exciton spectra and the defect or impurity structure of the crystal. A line associated with a neutral donor and a pair of lines associated with an ionized donor were found for the very purest material. Lithium doped crystals showed several pairs of ionized donor lines as well as many characteristic neutral donor lines. Silver doping produced a large number of characteristic lines, but the nature of the associated centers has not been established. Sodium, potassium and rubidium doped crystals each showed characteristic neutral donor lines as well as many lines which could not be studied.