Vibronic transitions of U 3+ -doped LaBr 3 single crystals

Good quality U 3+ -doped LaBr 3 single crystals have been obtained by the Bridgman–Stockbarger method. High-resolution low temperature emission spectra were recorded in a wide spectral range and are discussed. The emission from the 2 K 15/2 , 2 H 11/2 , and 4 F 9/2 levels to the 4 I 9/2 ground state and from 2 K 15/2 to the first excited state 4 I 11/2 , have been investigated and are discussed with respect to vibronic transitions. The registered vibronic lines were compared with the Raman spectra of LaBr 3 single crystals.