Structural transformation in densified silica glass: A molecular-dynamics study

Journal Article · Fri Jul 01 00:00:00 EDT 1994 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.50.118· OSTI ID:7302913

Jin, W; Kalia, R K; Vashishta, P ^[1]; Rino, J P ^[2]

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1. Concurrent Computing Laboratory for Materials Simulations, Department of Physics Astronomy and Department of Computer Sciences, Louisiana State University, Baton Rouge, Louisiana 70803-4001 (United States)
2. Universidade Federal de Sao Carlos, 13560 Sao Carlos, Sao Paulo (Brazil)

Pressure-induced structural transformation and the concomitant loss of intermediate-range order (IRO) in high-density SiO[sub 2] glass are investigated with the molecular-dynamics (MD) approach. The MD simulations cover a wide range of mass densities---from normal density (2.20 g/cm[sup 3]) to the density corresponding to stishovite (4.28 g/cm[sup 3]). This twofold increase in the density produces significant changes in the short-range order and intermediate-range order. As the density increases from 2.20 to 4.28 g/cm[sup 3], the Si-O bond length increases from 1.61 to 1.67 A, the Si-O and O-O coordinations change from 4 to 5.8 and from 6 to 12, respectively, and the O-Si-O bond angle changes from 109[degree] to 90[degree]. These results provide firm evidence of structural transition from a corner-sharing Si(O[sub 1/2])[sub 4] tetrahedral network to a network of Si(O[sub 1/3])[sub 6] octahedra jointed at corners and edges. At normal density, the first sharp diffraction peak (FSDP) in the static structure factor [ital S]([ital q]) is at 1.6 A[sup [minus]1] whereas under pressure the height of the FSDP is considerably diminished and its position shifts to larger [ital q] values. At a density of 2.64 g/cm[sup 3], a peak in [ital S]([ital q]) appears at 2.85 A[sup [minus]1]. The height of this peak grows as the density increases. All of these results are in agreement with the recent high-pressure x-ray measurements on SiO[sub 2] glass.

• DOE Contract Number: FG05-92ER45477
• OSTI ID: 7302913
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 50:1; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
BOND ANGLE
BOND LENGTHS
CHALCOGENIDES
CRYSTAL-PHASE TRANSFORMATIONS
DIMENSIONS
GLASS
LENGTH
MINERALS
ORDER-DISORDER TRANSFORMATIONS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
SILICA
SILICON COMPOUNDS
SILICON OXIDES
STRUCTURE FACTORS