Correlation among electronic polarisability, optical basicity, interaction parameter and XPS spectra of Bi₂O₃-B₂O₃ glasses

The average electronic polarisability of the oxide ion (α_O^2-), optical basicity (Λ), Yamashita-Kurosawa's interaction parameter (A) and oxygen 1s (O1s) binding energy in x-ray photoelectron spectroscopy (XPS) of xBi₂O₃. (100-x)B₂O₃ glasses (x=0∼65) have been examined to check correlations among them and to clarify the electronic structure of the glasses and bonding character of Bi-O. Both α_O^2- and A increase gradually with increasing Bi₂O₃ content, and large α_O^2- values over 2 ų and large Λ values over 0.9 are obtained in the glasses with high Bi₂O₃ contents. The interaction parameter ranges from about 0·05 to 0·25 and decreases with increasing Bi₂O₃ content. The O1s peak in XPS spectra consists of two components: the O1s peak with higher binding energies, O1s(1), is assigned to B-O-B bonds and that with lower binding energies, O1s(2), corresponds to Bi-O-B and Bi-O-Bi bonds. The O1s(1) binding energy decreases gradually with increasing Bi₂O₃ content but the O1s(2) binding energy is almost constant suggesting that the ionic/covalent character of Bi-O bonds does not change significantly with composition. Close correlations are observed among α_O^2-, Λ, A and mean O1s binding energy. Particularly, it has been found that O1s binding energy is a good measure of the optical basicity of Bi₂O₃-B₂O₃ glasses and the interaction parameter gives good information about the electronic polarisability of oxide glasses as well as optical basicity. It is found that Bi-O bonds in Bi₂O₃-B₂O₃ glasses are more ionic compared with Sb-O bonds in Sb₂O₃-B₂O₃ glasses.