Uniform calculation of the optical and EPR spectral data for the trigonal (CrO6)9− octahedral clusters in Y3Al5O12 crystal

Abstract

The complete diagonalization (of the energy matrix) method is applied in this paper for the unified calculation of optical and EPR spectral data of the trigonal (CrO6)9− octahedral clusters in Y3Al5O12 (YAG) crystal. The method is based on the two-spin–orbit-parameter model where, besides the contributions from the spin–orbit parameter of central dn ion in the traditional crystal-field theory, those from the spin–orbit parameter of ligand ions via the covalence effect are considered. The computed 32 spectroscopic data values (29 crystal field energy levels and three spin-Hamiltonian parameters, namely the g factors g// and g⊥, and the zero-field splitting D) are in reasonable agreement with the experimental values, despite using only four adjustable parameters. This suggests that the method is valid in the uniform calculation of optical and EPR spectral data for d3 ions in crystals. The impurity-induced angular distortion of the (CrO6)9− clusters in YAG crystal was also evaluated.