Crystal field studies of the MgAl₂O₄: Ni²⁺ ground and excited state absorption

The exchange charge model of crystal field theory has been used to analyze the ground and excited state absorption of octahedrally coordinated Ni ²⁺ ion in MgAl₂O₄. The parameters of the crystal field acting on the Ni²⁺ ion are calculated from the crystal structure data. The obtained energy level schemes were compared with experimental ground and excited state absorption spectra; a good agreement with experimental data is demonstrated. From the analysis of the experimental spectra, the Stokes shift, the effective phonon energy and the zero-phonon line position all were evaluated.