A neutron diffraction investigation of the structure of vitreous zinc chloride

Desa, J.A.E.; Wright, Adrian C.; Wong, Joe; Sinclair, Roger N.

doi:10.1016/0022-3093(82)90189-2

Cited by 117 publications

(29 citation statements)

References 61 publications

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“…The figure also shows the analogous distribution obtained from the bulk glass at ambient pressure using PIM, which is similar to distributions observed in bulk silicates [30,31]. The bulk distribution is significantly broader than those generated for the bilayer with θ ∼ 145 • and ∆θ ∼ 36 • .…”

supporting

confidence: 71%

Refining glass structure in two dimensions

et al. 2017

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Recently determined atomistic scale structures of near-two dimensional bilayers of vitreous silica (using scanning probe and electron microscopy) allow us to refine the experimentally determined coordinates to incorporate the known local chemistry more precisely. Further refinement is achieved by using classical potentials of varying complexity; one using harmonic potentials and the second employing an electrostatic description incorporating polarization effects. These are benchmarked against density functional calculations. Our main findings are that (a) there is a symmetry plane between the two disordered layers; a nice example of an emergent phenomenon, (b) the layers are slightly tilted so that the Si-O-Si angle between the two layers is not $180^{\circ}$ as originally thought but rather $175 \pm 2 ^{\circ}$ and (c) while interior areas that are not completely imagined can be reliably reconstructed, surface areas are more problematical. It is shown that small crystallites that appear are just as expected statistically in a continuous random network. This provides a good example of the value that can be added to disordered structures imaged at the atomic level by implementing computer refinement.Comment: 5 pages, 4 figure

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confidence: 71%

Refining glass structure in two dimensions

et al. 2017

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“…The highest temperature reached by the TMD falls from BeF2false⟶SiO2false⟶GeO2false⟶H2O. The inset to the figure shows the mean M–X–M bond angles, θ¯MXM, that is, the bond angles between neighbouring MX4 tetrahedra for the BeF2 model over the full range of polarizabilities studied along with experimental values for BeF2, SiO2 and GeO2 [77]. There is a clear correlation between the temperature scale at which the TMD locus emerges and the mean inter-tetrahedral bond angle, again as this bond angle is an effective measure of the energetic balance between local high and low density environments.…”

Section: Discussionmentioning

confidence: 99%

“…SiO2, GeO2 and BeF2 show structural similarities in the sense that the nearest-neighbour coordination polyhedra are MX4 tetrahedra. However, their ordering beyond the short-range may differ as the bridging bond angles between neighbouring tetrahedra vary from θ¯normalMXM≃130∘ for GeO2, to θ¯normalMXM≃145∘ for SiO2, to θ¯normalMXM≃155∘ for BeF2 [77]. The M–X–M bond angles are controlled by many-body (ion polarization) interactions [78,79].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic anomalies, polyamorphism and all that

Fijan,

Wilson

2023

Phil. Trans. R. Soc. A.

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The appearance and evolution of thermodynamics anomalies, and related properties, are studied for two classes of system, modelling those dominated by covalent and ionic interactions, respectively. Such anomalies are most familiar in the density but are also present in other thermodynamics variables such as the compressibility and heat capacity. By systematically varying key model parameters the emergence and evolution of these anomalies can be tracked across the phase space. The interaction of the anomalies can often be rationalized by thermodynamics ‘rules’. The emergence of these anomalies may also be correlated with the appearance of polyamorphism, the existence of multiple amorphous states which differ in density and entropy. This article is part of the theme issue ‘Exploring the length scales, timescales and chemistry of challenging materials (Part 1)’.

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“…In addition, for the present glass, it should be noted that electron densities of GeO 2 and GeS 2 glasses are not very different (330 and 250 electrons/nm 3 ) because the atomic electron densities (8 and 16/atom) of O for S tend to counterbalance the macroscopic densities of GeO 2 and GeS 2 (3.7 and 2.7 g/cm 3 ). 9) Probably due to the first reason, meaningful images of GeO 2 could not be obtained. However, for GeS 2 and 50GeO 2 -50GeS 2 , we can obtain TEM images having a reproducible difference; i.e., a smooth image of GeS 2 and a contrast fluctuated one with a scale of $10 nm in 50GeO 2 -50GeS 2 .…”

Section: Temmentioning

confidence: 99%

Nanoscale Heterogeneous Structures in GeO₂–GeS₂ Glasses

Terakado

Tanaka

2008

jjap

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We use the analytic continuation procedure proposed in our earlier works to study the thermodynamics of black holes in 2 + 1 dimensions. A general black hole in 2 + 1 dimensions has g handles hidden behind h horizons. The result of the analytic continuation of a black-hole spacetime is a hyperbolic 3-manifold having the topology of a handlebody. The boundary of this handlebody is a compact Riemann surface of genus G = 2g + h − 1. Conformal moduli of this surface encode in a simple way the physical characteristics of the black hole. The moduli space of black holes of a given type (g, h) is then the Schottky space at genus G. The (logarithm of the) thermodynamic partition function of the hole is the Kähler potential for the Weil-Peterson metric on the Schottky space. The Bekenstein bound on the black-hole entropy leads us to conjecture a new strong bound on this Kähler potential.PACS number: 04.70.D

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A neutron diffraction investigation of the structure of vitreous zinc chloride

Cited by 117 publications

References 61 publications

Refining glass structure in two dimensions

Refining glass structure in two dimensions

Thermodynamic anomalies, polyamorphism and all that

Nanoscale Heterogeneous Structures in GeO₂–GeS₂ Glasses

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A neutron diffraction investigation of the structure of vitreous zinc chloride

Cited by 117 publications

References 61 publications

Refining glass structure in two dimensions

Refining glass structure in two dimensions

Thermodynamic anomalies, polyamorphism and all that

Nanoscale Heterogeneous Structures in GeO2–GeS2 Glasses

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Product

Resources

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Nanoscale Heterogeneous Structures in GeO₂–GeS₂ Glasses