On the Superhyperfine Parameters of K₂PdX₄:Cu²⁺

The simplified perturbation formulas of the superhyperfine parameters for a 3d9 ion in tetragonally elongated octahedra are established from the crystal-field model and the cluster approach. In these expressions, the relationships are obtained for the orbital mixing coefficients, unpaired spin densities, and average covalence factor. The simplified formulas are applied to the Cu2+ centers in K2PdX4(X=Cl, Br). The calculated results show the agreement with the experimental data and the theoretical values based on the complicated molecular orbital calculations in the previous work.