Theoretical Studies of the Local Structures and EPR Spectra for VO~(2+) in MB_4O_7 (M = Zn, Cd) Glasses

摘要

Electron spin resonance spectral parameters (g factors g_‖, g_⊥ and hyperfine structure constants A_‖, A_⊥) of a tetragonal V~(4+) centers in MB_4O_7 (M = Zn, Cd) are theoretically investigated by using the perturbation formulae for a 3d1 ion in tetragonally compressed octahedra. In these formulae, the contributions to the g factors from the tetragonal distortion, characterized by the tetragonal field parameters D_s and D_t are taken into account by considering the local structures of the ligand octahedron around the V~(4+) due to the Jahn-Teller effect. Based on the calculations, the ligand octahedra around V~(4+) are suggested to suffer about 5.7% and 4.3% relative compression along C_4 axis for MB_4O_7 glasses with M = Zn and Cd, respectively, and negative signs of the hyperfine structure constants A_‖ and A_⊥ for V~(4+) centers in MB_4O_7 glasses were suggested in the discussion.