Theoretical Investigations of the Local Structure Distortion and EPR Parameter for Ni²⁺-doped Perovskite Fluorides

By analyzing the optical spectra and electron paramagnetic resonance parameter D, the local structure distortion of (NiF₆)^4- clusters in AMF₃ (A=K, Rb; M=Zn, Cd, Ca) and K₂ZnF₄ series are studied using the complete energy matrix based on the double spin-orbit coupling parameter model for configuration ions in a tetragonal ligand field. The results indicate that the contribution of ligand to spin-orbit coupling interaction should be considered for our studied systems. Moreover, the relationships between D and the spin-obit coupling coefficients as well as the average parameter and the divergent parameter are discussed.