Polarized laser excitation, electron paramagnetic resonance, and crystal-field analyses of Sm3+-doped LiYF4

Using both optical absorption and laser-excited fluorescence, we have deter mined 55 crystal-field energy levels of the Sm3+ center in LiYF4:Sm3+. Elec tron paramagnetic resonance determines the symmetry of the center to be tet ragonal, with effective spin Hamiltonian parameters of g(parallel to) = 0.4 10 +/- 0.005 and g(perpendicular to) = 0.614 +/- 0.002. Inclusion of hyperf ine interactions yields magnetic hyperfine constants of A(parallel to) = 20 5 +/- 5 MHz and A(perpendicular to) = 735 +/- 5 MHz for the Sm-147 isotope and A(parallel to) = 165 +/- 5 MHz and A(perpendicular to) = 605 +/- 5 MHz for the Sm-149 isotope. Truncating the 4f(5) configuration to the lowest 30 multiplets, D-2d symmetry crystal-field fits to the experimental energy le vels yield physically reasonable crystal-field parameters with standard dev iations under 11 cm(-1). Simultaneous diagonalization of the crystal- and m agnetic-field perturbation matrices give calculated magnetic splitting fact ors in good agreement with the measured ground-stare g factors. [S0163-1829 (99)12929-1].