Studies on spin Hamiltonian parameters and local structures for v4+ in BaCl2-BaO-B2O3 glasses at various BaCl2 compositions

Abstract

ABSTRACT The spin Hamiltonian parameters (SHPs), local structure and their composition dependences for impurity V4+ in xBaCl2-(30–x)BaO-68B2O3-2V2O5 (x = 0, 2, 5, 10 mol%) glasses are theoretically analyzed by using the perturbation formulae of SHPs for octahedral 3d1 clusters with tetragonal compression. The power law composition functions for the relevant quantities (covalency factor N, relative tetragonal compression ratio ρ, core polarisation constant κ and reduction factor H) suitably recur the experimental composition dependences of the SHPs for V4+. N shows the firstly fast and then slow decreasing trend, whereas ρ, κ and H exhibit the firstly fast and then slow increasing tendencies. The above composition dependences can be attributed to the modifications of the local structure and electron cloud distribution near the impurity V4+ due to the doped chlorine in participating in the formation and modification of the glasses network and mixed alkali effect.