Studies on the local structure and spin Hamiltonian parameters for V⁴⁺ in Na₂ O-PbO-Bi₂ O₃ -SiO₂ glass ceramics

The local structure, d-d transition band, and spin Hamiltonian parameters (SHPs) are theoretically studied for the V⁴⁺ probe in Na₂ O-PbO-Bi₂ O₃ -SiO₂ (NPBS) glass ceramics containing V₂ O₅ dopant with various concentration x (0 ≤ x ≤ 5 mol%) by using the perturbation formulas of the SHPs for tetragonally compressed octahedral 3d¹ clusters. The first decreasing (or increasing) and then increasing (or decreasing) d-d transition band (= 10 D_q ) and hyperfine structure constants A_// and A_⊥ (or g factors g_// and g_⊥ ) with x can be suitably simulated with the similarly varying Fourier type concentration functions of cubic field parameter D_q , covalence factor N, core polarization constant κ, and reduction factor H (or relative tetragonal compression ratio ρ), with the minima (or maxima) at the middle concentration x = 3 mol%, respectively. The above concentration variations of SHPs and the related quantities may originate from the modifications of local crystal field strength, tetragonal compression, and electron cloud distribution near the impurity V⁴⁺ with x, corresponding to the highest [V⁴⁺ ]/[V⁵⁺ ] ratio at 3 mol%. Present studies would be helpful to explore novel sodium lead bismuth silicate glass ceramics by modifying the concentration of V₂ O₅ dopant.