Identification of chromium and nickel sites in zinc phosphate glasses

Optical and EPR investigations of chromium and nickel doped zinc phosphate glasses are carried out at room temperature to evaluate crystal field, spin-Hamiltonian and bonding parameters. For Cr3+ ion, the site symmetry is ascribed to a distorted octahedron, whereas the Ni2+ ion is located in a near octahedral site. In addition, the bonding parameters suggest covalent nature for Cr3+ and a moderate covalent nature for Ni2+ in the zinc phosphate glasses.