Investigation on the Spin Hamiltonian Parameters and the Local Structures for Cu2+ Centers in Sodium Phosphate and Heavy Metal Fluoride Glasses

The spin Hamiltonian parameters (the anisotropic g factors gII, g⟂ and hyperfine structure constants AII, A⟂) for the Cu2+ sites in sodium phosphate glasses Na2O-9P2O5 and heavy metal fluoride glasses 60ZrF4-5LaF3 -20BaF2-15NaF are theoretically investigated by using the high (fourth-) order perturbation formulas of these parameters for a 3d9 ion in tetragonally elongated octahedra. In these formulas, the contributions to the g factors from the tetragonal distortion, characterized by the tetragonal field parameters Ds and Dt, are taken into account by considering the relative axial elongation of the ligand octahedron around the Cu2+ due to the Jahn-Teller effect. According to the calculations, the ligand octahedra around Cu2+ are suggested to suffer about 12% and 18% relative elongation along the C4-axis for the studied Na2O-9P2O5 and 60ZrF4 -5LaF3-20BaF2 -15NaF glasses, respectively. The local structures characterized by the above axial elongations are discussed