Computations of the crystal field energy levels and spin-Hamiltonian parameters for Cr3+ centers in LiGa5O8 crystal

Abstract

In this paper, we adopt the complete diagonalization (of energy matrix) method to compute uniformly the crystal field energy levels (obtained from optical spectra) and spin-Hamiltonian parameters (g factor g//, g⊥ and zero-field splitting D, obtained from EPR experiment) for the approximately trigonal Cr3+ center in inverse spinel LiGa5O8 crystal. This diagonalization method is based on the two-spin-orbit-parameter model which considers the contributions from both the spin-orbit parameter of central dn ion (in the classical crystal field theory) and that of ligand ions. The results indicate that the observed 17 optical bands (or crystal field energy levels) and three spin-Hamiltonian parameters of LiGa5O8:Cr3+ crystal can be reasonably and uniformly interpreted by the method with only four adjustable parameters. The local anion distribution parameter uloc in the Cr3+ center in LiGa5O8 crystal is also estimated.