Spectroscopic investigations of the PbO–MoO3–P2O5:V2O5 glass system

Abstract

V2O5 doped PbO–MoO3–P2O5 glasses were prepared by melt-quenching and the amorphous nature of these samples was confirmed by XRD. EPR data indicate the presence of V4+ ions in a square-pyramidal coordination (C4v). The experimental EPR spectra were simulated assuming a superposition of two signals; one with hyperfine structure (HFS) typical for isolated ions and the other one consist of a broad line without HFS characteristic of clustered ions. The optical absorption spectra of the glassesexhibited two broad absorption bands corresponding to 2 B2Æ2 B1 and 2 B2Æ2 E transitions of VO2+ ions, with increasing concentration of V2O5, the half width and peak height of these bands were observed to increase. The IR bands of phosphate groups were strongly reduced for 0·6 mol% of V2O5 due to the depolymerisation of the phosphate network and to the appearance of new vibrations characteristic of P–O–V and V–O–V linkages showing the network former role of V2O5.