Crystal field analysis of energy level structure of LiAlO ₂:V³⁺ and LiGaO₂:V³⁺

A detailed analysis of the energy level structure of tetrahedrally coordinated V³⁺ ion in lithium aluminum oxide LiAlO₂ (γ-phase) and lithium dioxogallate LiGaO₂ is performed using the exchange charge model of the crystal field theory. The parameters of the crystal field acting on the V³⁺ optical electrons are calculated from crystal structure data assuming C₁ point symmetry of the [VO₄]^5- impurity center in LiAlO₂ and LiGaO₂. Crystal field splitting of all five LS terms of the V ³⁺ ion (³F, ³P, ¹S, ¹D, ¹G) is calculated. The energy levels obtained are compared with experimental absorption spectra and results of application of other crystal field models (the angular overlap model and Racah theory) to the considered crystals; though only one fitting parameter of the exchange charge model was used, a good agreement with experimental data on the ground and excited state absorption is demonstrated.