Ab initio cluster model calculations on the vibrational frequencies of TeO2 glass

Vibrational frequencies of TeO2 glass and their Raman scattering intensities have been computed at the Hartree-Fock level using small clusters modeling of the local structure of TeO2 glass. The calculations have successfully reproduced the observed Raman spectra of TeO2 glass. The calculated normal-mode coordinates have shown that the observed Raman bands at around 640 cm(-1) are attributed to the vibrations localized within the TeO2 trigonal bipyramid, while the vibrations in the ranges 400-500 cm(-1) and 720-780 cm(-1) an due to the vibrations localized within the Te-O-eq(ax)-Te linkage.