EPR investigation of the site symmetry of Fe3+ ions in the spinel crystals

The site symmetry of Fe3+ ions doping in the spinel crystals (MgAl2O4, ZnAl2O4) and the local lattice structure around the impurity ion have been studied by diagonalizing the complete energy matrices for a d5 configuration ion in a trigonal ligand-field and simulating the EPR parameters D and (a−F). The calculation indicates that when the local lattice structure of Fe3+ ion located at octahedral site is distorted slightly, the site symmetry for Fe3+ ion is still D3d but not C3v.