Low-frequency Raman scattering in alkali tellurite glasses

Abstract

Raman scattering has been employed to study the alkali-cation size dependence and the polarization characteristics of the low-frequency modes for the glass-forming tellurite mixtures, 0⋅1M 2 O-0⋅9TeO 2 (M = Na, K, Rb and Cs). The analysis has shown that the Raman coupling coefficient alters by varying the type of the alkali cation. The addition of alkali modifier in the tellurite network leads to the conversion of the TeO 4 units to TeO 3 units with a varying number of non-bridging oxygen atoms. Emphasis has also been given to the lowfrequency modes and particular points related to the low-frequency Raman phenomenology are discussed in view of the experimental findings.

Influence of lattice modifier on the nonlinear refractive index of tellurite glass

“…5. A band at 442 cm −1 was identified by symmetrical stretching of linkages Te-O-Te [27], at~660 cm −1 to the Te-O-Te antisymmetric stretching vibration of TeO 4 units, and at 750 cm −1 to the Te˭O bonding, involving a three-coordinate tellurium atom (O=TeO2) [28]. It can be seen in the spectra that adding a lattice modifier to the TL glass matrix causes a structural change.…”

Unraveling the role of microenvironment and hydrodynamic forces on the vibrational relaxation rates of pyridine–water complexes

“…Details for the advantages in using the reduced as well as the iso and aniso representations in analyzing the spectra can be found elsewhere [25].…”

Manifestation of thermodynamic glass transition by structure and picosecond dynamics in alkali tellurite glasses

“…Proceeding to a quantitative presentation of the low-frequency Raman spectra we performed a fitting procedure that is relatively simple and does not involve a large number of parameters and approximations. We have used the superposition scheme where the QE line is for simplicity treated as a Lorentzian, the Boson peak is described by a lognormal distribution with a few adjustable parameters and the low-lying vibrations as Gaussian distributions [14,17,39]. The variation of the Boson peak maximum with temperature is shown in Fig.…”

“…Refs. [6][7][8][9][10][11][12][13][14]). The outcome of these studies pertains to two basic findings: first, the pure TeO 2 consists of TeO 4 trigonal bipyramids (tbp's), in which one equatorial site of the sp 3 d hybrid orbitals is occupied by a lone pair of electrons and the other two equatorial and axial sites are occupied by oxygen atoms.…”

“…The outcome of these studies pertains to two basic findings: first, the pure TeO 2 consists of TeO 4 trigonal bipyramids (tbp's), in which one equatorial site of the sp 3 d hybrid orbitals is occupied by a lone pair of electrons and the other two equatorial and axial sites are occupied by oxygen atoms. Second, the addition of alkali and/ or alkaline earth modifiers to pure TeO 2 network causes a change in the Te coordination polyhedron from TeO 4 tbp to TeO 3 trigonal pyramid (tp) in which one of the Te sp 3 hybrid orbitals is occupied by a lone pair of electrons [6][7][8][9][10][11][12][13][14]. Recently, the intramolecular and intrermolecular dynamics have been studied in tellurite based glass-forming system [15].…”