Is simulated amorphous'' silica really amorphous

Conference · Sun Jul 10 04:00:00 EDT 1994 · AIP Conference Proceedings (American Institute of Physics); (United States)

OSTI ID:6915976

Binggeli, N ^[1]; Chelikowsky, J R ^[2]

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1. Institut Romand de Recherche Numerique en Physique des Materiaux (IRRMA), PHB Ecublens, 1015 Lausanne (Switzerland)
2. Department of Chemcial Engineering and Materials Science, Minnesota Supercomputer Institute, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

We have carried out extensive molecular dynamics simulations for the pressure induced amorphization of quartz by means of a classical force-field model. In agreement with earlier simulations, we find that a phase transition occurs within the experimental pressure range of the amorphization. However, in contrast to the interpretation of previous simulations, we demonstrate that the new phase is [ital not] amorphous, since the correlation functions for the equilibrated structure can be shown to be consistent with those of a crystalline phase. In addition, two transformations to ordered structures are found to occur sequentially during the simulations. The first transformation is likely to be related to the recently discovered transition of quartz to an intermediate crystalline phase before its amorphization. The second transformation, instead, yields a compact, octahedrally coordinated Si sublattice. The latter may be an artifact of the pair-potential simulation. [copyright] 1994 American Institute of Physics

• OSTI ID: 6915976
• Report Number(s): CONF-921145--
• Conference Information: Journal Name: AIP Conference Proceedings (American Institute of Physics); (United States) Journal Volume: 309:1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
AMORPHOUS STATE
CHALCOGENIDES
COMPUTERIZED SIMULATION
CORRELATION FUNCTIONS
FUNCTIONS
INTERATOMIC FORCES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
SILICON COMPOUNDS
SILICON OXIDES
SIMULATION
VERY HIGH PRESSURE