Simulation of the energy level scheme of Nd³⁺and Eu³⁺ions in rare-earth orthovanadates and phosphates

The absorption spectra of the Nd 3+ ion in the tetragonal xenotime-type NdVO 4 and in the monoclinic monazite-type LaVO 4 , LaPO 4 and NdPO 4 as well as the luminescence of the Eu 3+ ion in LaVO 4 and LaPO 4 were measured and the spectra were analysed according to the appropriate symmetry of the RE site. In addition to pure zero-phonon electronic lines the absorption spectra of the Nd 3+ ion showed extensive vibronic side bands which were identified with the aid of the measured Raman scattering spectra of LaVO 4 :Nd 3+ and NdVO 4 . Based on the energy level schemes derived from the absorption and luminescence spectra the parametrization of the free-ion and crystal-field effects were carried out with good results as indicated by the low RMS deviation values. The parameter sets for Nd 3+ and Eu 3+ ions in the same matrices are consistent with each other but no correlation was found between sets for matrices of different structures.