SPECTROSCOPIC PROPERTIES AND SIMULATION OF THE ENERGY-LEVEL SCHEMES OF ND3+ AND PR3+ IONS IN RARE-EARTH TELLURIUM OXIDES

Absorption and emission measurements at liquid-helium temperature, liquid-nitrogen temperature and room temperature have been performed on monoclinic RE2Te4O11 (RE = Nd3+, Pr3+), on rare-earth tellurium oxides and on Pr-doped Gd2Te4O11 samples, respectively. The rare earth occupies a single crystallographic position with a low point symmetry C1. The spectra were analysed according to the crystal-field theory. From the experimental data, nearly complete energy level schemes of the Pr3+ and Nd3+, on the 4f2 and 4f3 configurations, were derived. Very good correlation was obtained between the experimental and simulated energy level schemes, for the approximate C2v and/or C(s) site symmetries. The crystal-field parameters vary smoothly with the atomic number of the rare earth, when compared with those determined previously for Eu3+ in the same matrix.