Mechanisms of network collapse in GeO(2) glass: high-pressure neutron diffraction with isotope substitution as arbitrator of competing models

Kamil Wezka, Philip S Salmon, Anita Zeidler, Dean A J Whittaker, James W E Drewitt, Stefan Klotz, Henry E Fischer, Dario Marrocchelli

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

The structure of the network forming glass GeO(2) is investigated by making the first application of the method of in situ neutron diffraction with isotope substitution at pressures increasing from ambient to 8 GPa. Of the various models, the experimental results are in quantitative agreement only with molecular dynamics simulations made using interaction potentials that include dipole-polarization effects. When the reduced density ρ/ρ(0) ≳ 1.16, where ρ(0) is the value at ambient pressure, network collapse proceeds via an interplay between the predominance of distorted square pyramidal GeO(5) units versus octahedral GeO(6) units as they replace tetrahedral GeO(4) units. This replacement necessitates the formation of threefold coordinated oxygen atoms and leads to an increase with density in the number of small rings, where a preference is shown for sixfold rings when ρ/ρ(0) = 1 and fourfold rings when ρ/ρ(0) = 1.64.
LanguageEnglish
Article number502101
JournalJournal of Physics-Condensed Matter
Volume24
Issue number50
DOIs
StatusPublished - 19 Dec 2012

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Neutron diffraction
Isotopes
neutron diffraction
Substitution reactions
isotopes
substitutes
Glass
glass
rings
Molecular dynamics
Polarization
Oxygen
Atoms
oxygen atoms
Computer simulation
dipoles
molecular dynamics
polarization
simulation
interactions

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Mechanisms of network collapse in GeO(2) glass : high-pressure neutron diffraction with isotope substitution as arbitrator of competing models. / Wezka, Kamil; Salmon, Philip S; Zeidler, Anita; Whittaker, Dean A J; Drewitt, James W E; Klotz, Stefan; Fischer, Henry E; Marrocchelli, Dario.

In: Journal of Physics-Condensed Matter, Vol. 24, No. 50, 502101, 19.12.2012.

Research output: Contribution to journalArticle

Wezka, Kamil ; Salmon, Philip S ; Zeidler, Anita ; Whittaker, Dean A J ; Drewitt, James W E ; Klotz, Stefan ; Fischer, Henry E ; Marrocchelli, Dario. / Mechanisms of network collapse in GeO(2) glass : high-pressure neutron diffraction with isotope substitution as arbitrator of competing models. In: Journal of Physics-Condensed Matter. 2012 ; Vol. 24, No. 50.
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