Sm2+ Spectra in Lanthanum Fluoride

Optical spectra and conductivity of LaF3, containing Sm2+, were studied. Three groups of emission lines near 560-620 nm, 650-690 nm and 680-770 nm at 7.9 K were attributed to the transitions from 5D2, 5D1, 5D0 to 7Fj levels of Sm2+. Emission of 5D0 has decay time 8.9 ms and quenching at temperatures 70-160 K. The linear dependence between conductivity and absorption coefficient of Sm2+ bands was observed. The dependence associated with presence of anion vacancy, which compensates insufficient charge of Sm2+ ions. Longest wavelength absorption band at 600 nm was absented in the excitation spectrum. The band was attributed to transitions from 4f6 of Sm2+ to vacancy level. Lesser wavelength absorption bands belong to 4f-5d transitions of Sm2+ ions.