Energy levels and line intensities ofPr3+in LiYF4

High-resolution polarized absorption and fluorescence spectra of ${\mathrm{Pr}}^{3+}$ in LiY${\mathrm{F}}_{4}$ were measured at temperatures between 10 and 300\ifmmode^\circ\else\textdegree\fi{}K. Energy-level assignments were made assuming electric-dipole transition selection rules for ${S}_{4}$ site symmetry. Forty-six energy levels of the $4{f}^{2}$ ground configuration were established, including 44 in the lowest nine multiplets. Crystal-field parameters were determined that gave a rms deviation of 15.8 ${\mathrm{cm}}^{\ensuremath{-}1}$ between 41 of the experimental energy levels and calculated values. The parameters were ${B}_{20}=488.9$, ${B}_{40}=\ensuremath{-}1043$, ${B}_{44}=1242$, ${B}_{60}=\ensuremath{-}42$, Re ${B}_{64}=1213$, and Im ${B}_{64}=22.5$ ${\mathrm{cm}}^{\ensuremath{-}1}$. These parameters were used to obtain the remaining energy levels, yielding a complete energy-level scheme for the $4{f}^{2}$ configuration of ${\mathrm{Pr}}^{3+}$. The crystal-field parameters for ${\mathrm{Pr}}^{3+}$ in LiY${\mathrm{F}}_{4}$ 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.