ENERGY-LEVELS AND LINE-INTENSITIES OF PR-3+ IN LIYF4

High-resolution polarized absorption and fluorescence spectra of Pr3+ in LiYF4 were measured at temperatures between 10 and 300°K. Energy-level assignments were made assuming electric-dipole transition selection rules for S4 site symmetry. Forty-six energy levels of the 4f2 ground configuration were established, including 44 in the lowest nine multiplets. Crystal-field parameters were determined that gave a rms deviation of 15.8 cm-1 between 41 of the experimental energy levels and calculated values. The parameters were B20=488.9, B40=-1043, B44=1242, B60=-42, Re B64=1213, and Im B64=22.5 cm-1. These parameters were used to obtain the remaining energy levels, yielding a complete energy-level scheme for the 4f2 configuration of Pr3+. The crystal-field parameters for Pr3+ in LiYF4 were compared to those for other ions in this host. A theoretical calculation of line intensities was performed in which the odd-fold crystal-field parameters were obtained from a lattice sum. Line intensities were measured and compared with theory. © 1979 The American Physical Society.