ELECTRON-PARAMAGNETIC-RESONANCE AND OPTICAL-ABSORPTION SPECTRA OF CU2-X)K2O.70B(2)O(3) GLASSES( IONS IN XKI.(30)

Electron paramagnetic resonance and optical absorption studies were ma de on xKL. (30-x) K2O.70B(2)O(3) glasses doped with Cu2+ ions at room temperature. The optical absorption spectrum in all the glass samples exhibited a broad band corresponding to the d-d transition bands of Cu 2+ ion. The EPR spectra of all glasses have similar spectral features. Various spin Hamiltonian parameters were evaluated from the EPR spect ra and it was observed that the ground state of Cu2+ is d(x2-y2) orbit al, the Cu2+ ions being deposited in tetragonally distorted octahedral sites. From the optical and EPR data the bonding coefficients were ev aluated. The in plane sigma bonding was found to be moderately covalen t while the in plane pi bonding was ionic.