Optical study and crystal field analysis of praseodymium doped lanthanum metaborate

Abstract

Praseodymium doped lanthanum metaborate, La(BO2)3, is synthesized by solution chemistry. The title compound crystallizes in the monoclinic space group I2/c. The ten-fold coordinated rare earth ion is located in the C2 low point symmetry site. The optical and crystal field analyses of Pr3+ in this host lattice are presented. The absorption spectra are recorded from the visible to the far IR domain at 300 and 9 K. The low temperature absorption spectra show only one electronic line for 3H4 → 3P0 transition confirming a unique local environment for the rare earth ion in this metaborate phase. Under various Ar+ laser excitations, the emission of Pr3+ ion is detected from the 3P0 and 1D2 excited levels of the 4f2 ground configuration. A selective excitation in the 1D2 level was also performed. The electrostatic crystal field (cf) effect on the 4f2 configuration has been evaluated on the basis of the cf theory with nine phenomenological crystal field parameters (cfp) in the C2v point symmetry, using 54 (52) experimental cf levels deduced from the absorption and emission spectra. The final simulation is achieved with an r.m.s. of 16.1 (12.6) cm−1.