Energy levels and crystal field calculations of Nd3+ in the REBMO5 phases (RE=rare earth, M=Ge, Si)

Abstract The optical properties of mixed oxides from the RE 2 O 3 –B 2 O 3 –MO 2 chemical system (RE=rare earth; M=Ge, Si) with general formula REBMO 5 have been analyzed. The energy level scheme of the Nd 3+ ion in the two structural types NdBGeO 5 and NdBSiO 5 have been deduced from the absorption and emission spectra recorded at different temperatures between 4.2 and 300 K. The simulation has been carried out on the 109 energy levels found for NdBGeO 5 and 125 for NdBSiO 5 . The phenomenological crystal field parameters have been determined assuming a C 2v point symmetry for the rare earth in NdBGeO 5 and C 2 or C s in NdBSiO 5 . The r.m.s. standard deviation is 17.5 cm −1 for NdBGeO 5 and 18.1 cm −1 for NdBSiO 5 , indicating a satisfying agreement between the calculated and experimental levels.