Explanations of the EPR parameters for the rhombic Cr3+-V-M and Cr3+-Li+ centers in A(2)MF(4) (A = K, Rb, Cs; M = Mg, Zn, Cd) crystals

In this paper, we establish the high-order perturbation formulas of EPR zer o-field splittings D, E and g factors, g(x), g(y) and g(z) for 3d(3) ions i n a sort of rhombic symmetry where the symmetry axes and hence the crystal- field axes lie along the [001], [010] and [100] axes. From these formulas, the EPR parameters D, E, g(x), g(y) and g(z) for the rhombic Cr3+-V-M and C r3+-Li+ defect centers in the tetragonal A(2)MF(4) (A = K, Rb, Cs; M = Mg, Zn, Cd) fluorides are calculated by considering the suitable defect-induced lattice distortions. The results are in reasonable agreement with the obse rved values.