Luminescence and Symmetry Properties of Color Centers

A study has been made of the luminescent emission of $F$, $M$, and $R$ centers in NaCl, KCl, and LiF. When such centers are excited by polarized light, the resulting emission can be analyzed for polarization. This yields information on the symmetry properties of the emitting center. In the case of $M$ centers and of $F$ centers made at 77°K the results obtained are consistent with the models widely used for these centers.