Luminescence in La 3TaO 4Cl 6

Abstract

The luminescence properties of La 3TaO 4Cl 6 are reported and discussed. The rare earth ions Sm 3+, Eu 3+, Tb 3+, Dy 3+, and Tm 3+ show characteristic absorption and emission lines. For Sm 3+ and Eu 3+, broad absorption bands are also observed and are attributed to charge-transfer transitions. The line emissions of Tb 3+ are only from 5 D 4, even at low (1 at.%) concentration. Broad excitation and emission bands were observed with In 3+. These bands are attributed to In 3+Ta 5+ → In 4+Ta 4+ charge-transfer transitions. An additional broad absorption at 250 and 280 nm leading to broad emission at 410 nm is ascribed to OH − impurities.