Copyright © 2012 Shashidhar Bale and Syed Rahman. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Electron paramagnetic resonance and optical absorption studies of Bi₂O₃-ZnO-B₂O₃-Li₂O glasses were made by introducing Cu²⁺ as spin probe. The EPR spectra of Cu²⁺ in all the glass samples recorded in the X-band frequency have similar spectral features. The variation in glass composition influences the spin Hamiltonian parameters calculated from the spectra. The spin Hamiltonian parameters indicate that the Cu²⁺ ions are coordinated with six ligand atoms in a distorted octahedron elongated along one of the axes and the ground state of the Cu²⁺ is orbital. The optical absorption spectra exhibited a broad band corresponding to d-d transition bands of Cu²⁺ ion. The values of bonding parameters indicate a covalent nature for the in-plane σ bonding and pure ionic nature for the in-plane and out-of-plane bonding. The theoretical optical basicity parameter values were evaluated, and it was observed that the value of increases whereas decreases with the increase in optical basicity.