EPR and optical absorption by Cu2+ ions in ZnO−Li2O−Na2O−K2O−B2O3 glasses

Electron Paramagnetic Resonance (EPR) studies at room temperature in the x-band frequencies on xZnO−10Li2O−10Na2O−10K2O−(69−x)B2O3−1CuO (x=0,2,4,6 and 8 mole%) glass systems were reported. The non-linear variation of spin-Hamiltonian parameters with ZnO content indicated the change in the ligand field strength around Cu2+ ions in the host glass. The ground state of Cu2+ ions in the glass is designated as dx2−y2 orbital (2B1g) while the observed symmetry around it is tetragonally distorted octahedral. The molecular orbital coefficients α2, β2 and β12 are evaluated for Cu2+ doped samples. The non-linear variation in the values of parameters indicated mixed alkali effect in the glasses.