Polarized absorption and fluorescence spectra are reported forHo3+ (4f10)ions incorporated into single crystals of strontium fluorapatite,Sr5(PO4)3F,also known as SFAP. Site-selective excitation experiments indicate that, to within instrumental resolution, theHo3+ions occupy similar lattice sites havingCssymmetry. Spectra were obtained between 1940 and 400 nm at temperatures from 4 K to room temperature on crystals having the hexagonal structure[P63/m(C6h2)].Individual energy (Stark) levels for the fourteen lowest-energy multiplet manifolds ofHo3+ (4f10)were analyzed in detail. These manifolds include the5I8(ground state), the remaining5IJmanifolds,5FJ,5S2,3K8(2),5G6,and the3G5(2)manifolds. A Hamiltonian consisting of Coulombic, spin-orbit, and crystal-field terms was diagonalized over these manifolds in anLSJMJbasis set, which includes 146 crystal-quantum states, labeled either&Ggr;1or&Ggr;2,appropriate to the crystal-field symmetry ofCs.By varying the crystal-field parameters,Bnm,and the centroid for each manifold, we obtained agreement between 101 experimental and calculated Stark levels with a rms deviation of9 cm−1.An additional 15 Stark levels, not included in the original analyses, are predicted to within the rms deviation. The predicted symmetry label of each Stark level agrees with the experimental assignment based on the analysis of the polarized spectra. ©1997 American Institute of Physics.