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

• High order perturbation method is applied to study experimental EPR spectra. • Local environment and stability of glasses can be modified by halides. • Halides' electronegativities affect application in optical devices. • Optical basicities Λ th exhibit increase acidity and support above results. Local structure and the effect of halide on MX∙M 2 O∙B 2 O 3 (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, [CuO 6 ]10− and [VO 6 ]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∙M 2 O∙B 2 O 3 , 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 Λ th of BCBBV are found larger than PCPBC and PbX-PbO-B 2 O 3 glasses due to stronger ionicity of Ba than Pb. [ABSTRACT FROM AUTHOR]