Raman spectrum, quantum mechanical calculations and vibrational assignments of (95% α-TeO 2/5% Sm 2O 3) glass

Abstract

Chozen system of tellurite glasses doped with rare earth oxides (95% α-TeO 2 + 5% Sm 2O 3) was prepared by melt quenching. Consequently, the Raman spectrum (150–1250 cm −1) of the modified tellurite have been recorded. As a continuation to our normal coordinate analysis, force constants and quantum mechanical (QM) calculations for tbp TeO 4 4− (triagonal bipyramid, C 2v) and TeO 3+1; Te 2O 7 6− (bridged tetrahedral), we have carried out ab initio frequency calculations for tpy TeO 3 2− (triagonal pyramidal, C 3v and C s) and tp TeO 3 2− (triagonal planar, D 3h) ions. The quantum mechanical calculations at the levels of RHF, B3LYP and MP2 allow confident vibrational assignments and structural identification in the binary oxide glass (95% α-TeO 2 + 5% Sm 2O 3). The dominant three-dimensional network structures in the modified glass are triagonal pyramidal TeO 3 with minor features of short range distorted tbp TeO 4 and bridged tetrahedral unit of TeO 3+1, leading to a structure of infinite chain. Therefore, α-TeO 2/Sm 2O 3 (95/5%) glass experience structural changes from TeO 4 (tbp); Te 2O 7 (TeO 3+1) → TeO 3 (tpy).