Color centers in lead molybdate crystals

Color center formation in PbMoO4 crystals, originating from nonstoichiometric batch composition, BaO and Bi2O3 additions, high-temperature annealing of crystals, and UV illumination, is discussed. Additional optical absorption bands are identified. The photochromism of the crystals is shown to be due to charge exchange, Pb2+ + Mo(6+)reversible arrow Pb3+ + Mo5+, of the centers. (C) 2003 MAIK Nauka / Interperiodica.