材料期刊网

The formulas of the g-factors g(parallel to), g(perpendicular to) and the hyperfine structure constants A(parallel to), A(perpendicular to) for 3d(7) ions in tetragonal octathedral crystals are established from a cluster approach. Differing from previous formulas, in these formulas the role of configuration interaction (CI)- and covalency (CO)-effects is considered, and the parameters related to both effects are obtained from the optical spectra and the structural parameters of the studied crystal. From these formulas, the EPR parameters g(i) and A(i) for K2ZnF4:Co2+ are calculated. The results show good agreement with the observed values. The contributions to the EPR parameters g(i) and A(i) from the CI and CO effects, and the relationship between the sign of Delta g (=g(perpendicular to)-g(parallel to)) and the tetragonal distortion (elongated or compressed) of the ligand octahedron are discussed.