EPR theoretical study of local lattice structure in Al2O3:Fe3+ system Original Research Article

By analyzing the EPR spectrum of transition-metal ion Fe3+ in Al2O3:Fe3+ system, the local lattice structure around impurity Fe3+ ion in the crystal has been studied by means of the diagonalization of the energy matrices of the electron–electron repulsion, the ligand-field and the spin–orbit coupling for a d5 configuration ion in a trigonal ligand-field. Both the second-order and fourth-order EPR parameters D and (a−F) are taken simultaneously in the structural investigation. The results indicate that the two three-edge-pyramids elongated obviously along C3 axis. The two distortion angles Δθ1=−1.1±0.1°,Δθ2=−1.8° as well as the two Fe–O bond lengths R1=2.016 A, R2=1.907 A are determined, respectively.