Molecular dynamics study of the thermal behaviour of silica glass/melt and cristobalite

Keiji Yamahara, Keiji Okazaki, Katsuyuki Kawamura

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

The thermal behaviour of amorphous silica is compared with that of a high temperature form of cristobalite using molecular dynamics (MD) simulations, in order to understand the thermal behaviour of silica glass from an atomistic point of view. The MD simulations reproduce the α-β transition of cristobalite, the negative thermal expansion of β-cristobalite, and the density maximum of the silica melt. The thermal expansion of cristobalite is closely related to the distances between the first neighbour silicon atoms, which depend on the average Si-O-Si angle. On the other hand, the thermal expansion of amorphous silica is not directly correlated with the variation in the average Si-O-Si angle. The positive thermal expansion of silica glass is ascribed to the deformation of network-forming rings, not to the variations in the lengths of the nearest neighbour Si-O or Si-Si bonds. The density anomaly of the silica melt is caused by two opposite factors in the density variation with decreasing temperature: densification due to the increase in number of bridging bonds, and opening of the tetrahedral network in which 5- to 7-membered rings become dominant with a reduction in smaller rings.

Original languageEnglish
Pages (from-to)32-42
Number of pages11
JournalJournal of Non-Crystalline Solids
Volume291
Issue number1-2
DOIs
Publication statusPublished - Oct 2001
Externally publishedYes

Fingerprint

silica glass
Fused silica
Silicon Dioxide
Molecular dynamics
thermal expansion
Silica
molecular dynamics
silicon dioxide
Thermal expansion
rings
Computer simulation
densification
Densification
simulation
anomalies
Silicon
Atoms
Temperature
Hot Temperature
silicon

ASJC Scopus subject areas

  • Ceramics and Composites
  • Electronic, Optical and Magnetic Materials

Cite this

Molecular dynamics study of the thermal behaviour of silica glass/melt and cristobalite. / Yamahara, Keiji; Okazaki, Keiji; Kawamura, Katsuyuki.

In: Journal of Non-Crystalline Solids, Vol. 291, No. 1-2, 10.2001, p. 32-42.

Research output: Contribution to journalArticle

Yamahara, Keiji ; Okazaki, Keiji ; Kawamura, Katsuyuki. / Molecular dynamics study of the thermal behaviour of silica glass/melt and cristobalite. In: Journal of Non-Crystalline Solids. 2001 ; Vol. 291, No. 1-2. pp. 32-42.
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