E.S.R. and optical study of VO2+ in lithium zinc-phosphate glasses

Abstract

The E.S.R. and optical spectra of glasses of basic composition 30% Li₂ O-30% ZnO-40% P₂ O₅ doped with vanadium have been studied.

The partial substitution of ZnO with Al₂O₃ and PbO has a great effect on the chemical durability of the glasses but does not affect their magnetic and optical properties.

The E.S.R. and optical data suggest that the dxy orbital of the umpaired spin of the V(IV) specie is not bonded with the π orbitals of the in plane ligands while there is a strong σ bonding with the same ligands. The bonding between the vanadium and the vanadyl oxygen is only slightly covalent. The E.S.R. spectra show a large reduction of the line-width when the concentration of the V₂O₅ goes from 1% to 0.1% showing that the dipolar broadening gives the larger contribution to the E.S.R. line-width.