Crystal field studies of the Mn4+ energy levels in the perovskite, LaAlO3

• The energy level of Mn4+ in LaAlO3 is calculated using the exchange charge model of crystal field theory.
• The calculated energy levels match the experimental optical data.
• A comparative study pertaining to variations in crystal field splitting and Racah parameter (B) is presented.
• A dimensionless parameter is introduced to quantify the nephelauxetic effect.

The electronic energy levels of the Mn4+ (3d3) ion in the rhombohedral perovskite, LaAlO3, have been calculated using the exchange charge model of crystal field theory. The calculated Mn4+ energy levels are in good agreement with the experimental spectra that have been presented in the literature. The results of our calculations yield the crystal field splitting and Racah parameters of Dq = 2123 cm−1, B = 695 cm−1 and C = 2941 cm−1, with C/B = 4.2. A cross-cutting comparative study of the variation in the crystal field splitting and the Racah parameters of the octahedrally coordinated Mn4+ ion in a series of materials with the perovskite structure is also presented. We have also introduced a dimensionless parameter (β1) which quantifies the nephelauxetic effect and predicts the energy of the 2Eg → 4A2g emission transition in the perovskites.