Energy levels of Cr 3+ ions in C 3 i sites of Y 3Al 5O 12

Abstract

From an analysis of the ultraviolet absorption spectrum of Cr 3+ ions in Y 3Al 5O 12 we have obtained a sufficient number of energy levels to perform a crystal-field splitting calculation for Cr 3+ ions in sites of C 3i symmetry in the lattice. The Hamiltonian used included Coulombic, crystal-field (C 3i symmetry), spin-orbit interaction, and effective interconfiguration interaction terms and was diagonalized within the complete basis for 3d 3 atomic configuration. The calculated energy levels were compared with experimental levels up to 40000 cm −1. From the data, we have assigned 29 Stark levels to Cr 3+ ions in C 3+ sites which agree with calculated levels to within an rms deviation of 18 cm −1. The values of the parameters that give the best agreement are F (2) = 52724, F (4) = 38380, ξ = 252, α = 132, γ = −124, B 20 = 1091, B 40 = −21574, and B 43 = 27224 cm −1 (Dq= 1605, ν = 891, and ν′= −104.8 cm −1). The crystal-field splitting of Cr 3+ levels in S 4 lattice sites is also predicted with the use of the free-ion parameters obtained in this paper and a point-charge lattice-sum model.