Spectra, energy levels, and transition line-strengths for Sm3+: Y3Al5O12

Optical spectra and energy levels of the sextet, quartet, and doubler state s of Sm3+ (4f(5)) incorporated into single crystals of Y3Al5O12 (Sm3+:YAG), where YAG denotes yttrium aluminum garnet, are reported and analyzed at wa velengths between 560 and 280 MI. The analysis of energy (Stark) levels is based on a model Hamiltonian consisting of Coulombic, spin-orbit, and inter configurational terms for the 4f(5) atomic configuration of Sm3+ and crysta l-field terms in D-2 symmetry (the: site symmetry of the Sm3+ ions in the g arnet lattice). The Hamiltonian also includes contributions arising from:th e spin-correlated crystal field. Because of the strength of the crystal fie ld, the entire energy matrix is diagonalized within the complete 4f(5) SLJM (J) basis set representing 73 LS states, 198 L-2S + I(J) multiplets, and 10 01 doubly degenerate crystal-quantum states. In D-2 symmetry, all Stark lev els are characterized by the same irreducible representation ((2)Gamma(5)). Optimization between 314 calculated-to-observed Stark levels was carried o ut with a final rms deviation of 10 cm(-1). Eigenvectors obtained from the crystal-field splitting analysis are used to calculate transition line stre ngths originating from the ground-state Stark level to Stark levels in exci ted manifolds. The calculated line strengths are compared with experimental line strengths obtained from the absorption spectrum at 3.8 K. The line-st rength analysis is useful in identifying individual excited Stark levels as sociated with sextet, quartet, and doublet states strongly mixed by the cry stal field. [S0163-1829(99)09347-9].