Crystal field analysis of energy level structure of the Cr2O3 antiferromagnet

A detailed analysis of the energy level structure of the six-fold coordinated Cr³⁺ ion in the chromium oxide Cr₂O₃ is performed using the exchange charge model of the crystal field theory. Parameters of the crystal field acting on the Cr³⁺ optical electrons are calculated from the crystal structure data for the [CrO₆]⁹⁻ impurity center. The energy levels obtained are compared with the experimental absorption spectra for the considered crystal; a good agreement with experimental data is demonstrated. One possible explanation for the ultraviolet p₁ absorption band is proposed based on the results of crystal field calculations.