Abstract
Based on the analysis of the group-chain scheme, the crystal-field-level fitting has been carried out for :, in which the ions occupy site symmetry positions. The RMS of energy-level fitting is . The wavefunctions obtained were used to the study of magnetic, thermal and spectroscopic properties of the crystal. The calculated g-factors confirm Karayianis' partial g-sum rule. The temperature dependence of Schottky specific heat and magnetic susceptibility agrees well with the experimental data. Using the Judd - Ofelt parameter analysis, the parameters are fitted to the absorption spectra with , and (in ). Considering the radiative, nonradiative transition and cross-relaxation in , one set of rate equations is established to study the fluorescence dynamics. The relation between the ion's population density in the excited state and the doped ion concentration is discussed, and some useful inferences are drawn.