Raman spectra of MO1/2TeO2 (M = Li, Na, K, Rb, Cs and Tl) glasses

Sekiya, T.; Mochida, Norio; Ohtsuka, Atsushi; Tonokawa, Mamoru

doi:10.1016/s0022-3093(05)80393-x

Cited by 406 publications

(208 citation statements)

References 23 publications

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“…The structural units of crystalline CdTeO 3 are distorted TeO 3 trigonal pyramids that are linked to each other with Cd atoms. This arrangement is similar to the one found in tellurite glasses [40,41]. There are Cd and Te atoms each of which occupy two non-equivalent sites, and O atoms in six non-equivalent sites.…”

Section: Amorphous Cdteosupporting

confidence: 78%

Computer simulation study of amorphous compounds: structural and vibrational properties

et al. 2010

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Molecular dynamic (MD) simulations, both classical and ab initio, of amorphous GeO 2 (germania), Al 2 O 3 (alumina), and CdTeO compounds are presented. We focus our attention on the structural and vibrational properties, giving an atomic description of the short-and intermediate-range order. Amorphous germanium oxide under pressure was studied by means of classical MD simulations. At normal density, the analysis of the interatomic distances reveals that in the amorphous state there is a short-range order dominated by a slightly distorted (GeO 4 ) tetrahedron. Beyond that, there is an intermediaterange order composed by vertex-sharing tetrahedra. As density increases, there is a structural transformation, from a short-range order defined by the basic tetrahedron to a basic octahedron. Consistent with this picture, the vibrational density of states also presents big changes, where the low frequency band shrinks, and the high frequency becomes wider and flatter. In the case of alumina, both classical and first principles MD calculations of amorphous Al 2 O 3 are reported, comparing both methodologies. Interatomic correlations allow us to conclude that the shortrange order is mainly composed by AlO 4 tetrahedra, but in contrast to classical MD results, also an important number of AlO 5 unit is present. The vibrational density of states presents two main bands, a low frequency one related to the inter-tetrahedron vibration and a high frequency band related to the intra-tetrahedron vibration. Finally, we present an ab initio MD calculation for the complex ternary material CdTeO 3 . According our calculations, the shortrange order of this compound consists of a number of basic building blocks, greater than in the case of its crystalline counterpart. The compound is characterized using pair and angular distribution functions, coordination numbers, and a description of the molecular units of the compound. For example, Cd is coordinated by either six or five atoms. In the case of Te, the chemical unit is TeO 3 . The most frequent clusters are CdO 6 , CdO 5 , TeO 3 , and TeO 4 .

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Section: Amorphous Cdteosupporting

confidence: 78%

Computer simulation study of amorphous compounds: structural and vibrational properties

et al. 2010

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“…Gaussian analysis of the spectra was performed using the nonlinear regression method The origin of the main bands appearing in the reduced polarized (VV) Raman spectrum atoms [20,21] With increasing the GeO 2 content, the 457 cm -1 band of tellurite network merges with the 420 cm -1 band of pure GeO 2 , which is assigned to the symmetric stretching of bridging oxygen atoms (Ge-O-Ge) in 6-membered GeO 4 rings [25,29]. The ~347 and ~520 cm -1 bands in the GeO 2 rich spectra are attributed to D 1 and D 2 defect modes, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Currently, there exist a large amount of literature regarding the structure of pure TeO 2 and xM 2 O-(1-x)TeO 2 (M 2 O: alkali oxide, x: mole fraction) glasses with a variety of techniques such as X-ray diffraction [6][7][8], neutron diffraction [8,9], NMR [10][11][12], Mösbauer spectroscopy [13], EXAFS [14], ab initio quantum-mechanical calculations [15,16], molecular orbital calculations [9], Brillouin [17], IR [ 18,19] and Raman scattering [20][21][22][23]. However, a limited number of papers have been focused on binary glassy systems where both components are glassformers participating directly in the formation of the vitreous network.…”

Section: Introductionmentioning

confidence: 99%

Structural investigations of the xTeO2–(1−x)GeO2 (x=0, 0.2, 0.4, 0.6, 0.8 and 1) tellurite glasses: A composition dependent Raman spectroscopic study

Kalampounias

Nasikas

Papatheodorou

2011

Journal of Physics and Chemistry of Solids

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“…The local structure of alkali M2O-TeO2 glasses (M = Li, Na, and K) has been studied extensively using neutron diffraction [1][2][3][4][5], X-ray diffraction [6,7], EXAFS [7,8], Raman scattering [7,9,10], NMR [2,[11][12][13] and RMC modelling [2,14]. In these studies, particular emphasis was placed on determining the local environment of tellurium and there is a general consensus that the average tellurium coordination number, nTeO, decreases as an oxide modifier is added to the glass network, the change being driven by the bonding requirements of the modifier.…”

Section: Introductionmentioning

confidence: 99%

Alkali environments in tellurite glasses

Barney

Hannon

Holland

et al. 2015

Journal of Non-Crystalline Solids

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Neutron diffraction measurements are reported for five binary alkali tellurite glasses, xM2O·(100-x)TeO2 (containing 10 and 20 mol% K2O, 10 and 19 mol% Na2O, and 20 mol% 7 Li2O), together with 23 Na MAS NMR measurements for the sodium containing glasses.Differences between neutron correlation functions are used to extract information about the local environments of lithium and sodium. The Na-O bond length is 2.37(1) Å and the average Na-O coordination number, nNaO, decreases from 5.2(2) for x=10 mol% Na2O to 4.6(1) for x=19 mol% Na2O. The average Li-O coordination number, nLiO, is 3.9(1) for the glass with x=20 mol% Li2O and the Li-O bond length is 2.078(2) Å. As x increases from 10 to 19 mol% Na2O, the 23 Na MAS NMR peak moves downfield, confirming an earlier report of a correlation of peak position with sodium coordination number. The close agreement of the maximum in the Te-O bond distribution for sodium and potassium tellurite glasses of the same composition, coupled with the extraction of reasonable alkali coordination numbers using isostoichiometric differences, gives strong evidence that the tellurium environment in alkali tellurites is independent of the size of the modifier cation used.

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Raman spectra of MO1/2TeO2 (M = Li, Na, K, Rb, Cs and Tl) glasses

Cited by 406 publications

References 23 publications

Computer simulation study of amorphous compounds: structural and vibrational properties

Computer simulation study of amorphous compounds: structural and vibrational properties

Structural investigations of the xTeO2–(1−x)GeO2 (x=0, 0.2, 0.4, 0.6, 0.8 and 1) tellurite glasses: A composition dependent Raman spectroscopic study

Alkali environments in tellurite glasses

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