Dinuclear manganese centers in the manganese–lead–tellurate glasses

Abstract

FTIR, UV–VIS and EPR spectra of manganese doped lead–tellurate glasses with composition xMnO·(100 − x)[4TeO 2·PbO 2] where x = 0, 1, 5, 10, 20, 30, 40 mol% have been studied. The FTIR spectra show the formation of the Mn–O–Pb and Mn–O–Te bridging bonds by increasing of MnO concentration. The UV–VIS spectra show the Mn +3 species exhibit pronounced absorption, which masks the Mn +2 spin-forbidden absorption bands when Mn +2 ions are in high concentrations in these glasses. The EPR spectra exhibit resonance signals characteristic of Mn +2 ions. The resonance signal located at g ≈ 2 is due to Mn +2 ions in an environment close to octahedral symmetry, whereas the resonance at g ≈ 4.3 and 3.3 are attributed to the rhombic surroundings of the Mn +2 ions. The increase in the MnO content gives rise to absorption at g ≈ 2.4 and the paramagnetic ions are involved in dinuclear manganese centers.