FAcenters in cesium halides

Single crystals of CsCl, CsBr, and CsI doped with Li, Na, K, and Rb are grown from melt by the Bridgman technique, and were colored by the familiar Van Doorn method. $F_A$ centers are identified in the optical-absorption spectra of these crystals, recorded at room temperature and at liquid-nitrogen temperature. The energy levels of $F_A$ centers in cesium halides are calculated theoretically and compared with the experimental results.