Theoretical studies of the EPR spectra and local structures for Cu2+ and V4+ doped halo-borate glasses

Abstract

Local structure and the effect of halide on MX∙M2O∙B2O3 (M = Pb, Ba; X = F, Cl, Br) glasses doped with Cu2+ and VO2+ are investigated by means of the perturbation calculations of the spin Hamiltonian parameters (SHPs). Based on the fitted EPR results, [CuO6]10− and [VO6]8− clusters prefer to suffer the tetragonal elongation and compression distortions, respectively. Compare the ionic radius of Cu2+ with V4+ and Pb2+ with Ba2+ in MX∙M2O∙B2O3, the glasses with larger ionic radius of metal may induce larger tetragonal distortions and larger g anisotropies. The d-d transition bands show whole opposite trends for 3d9 and 3d1 impurities with the similar fluctuations due to the increase of non-bridging oxygen. The d-d transition bands and g factorsare are also analyzed from the electronegativities of incorporated halides. The values of basicities Λth of BCBBV are found larger than PCPBC and PbX-PbO-B2O3 glasses due to stronger ionicity of Ba than Pb.