Structural properties of molten silicates from ab initio molecular-dynamics simulations: Comparison between (formula presented) and (formula presented)

Magali Benoit, Simona Ispas, Mark Tuckerman

Research output: Contribution to journalArticle

Abstract

We present the results of first-principles molecular-dynamics simulations of molten silicates, based on the density functional formalism. In particular, the structural properties of a calcium aluminosilicate (formula presented) melt are compared to those of a silica melt. The local structures of the two melts are in good agreement with the experimental understanding of these systems. In the calcium aluminosilicate melt, the number of nonbridging oxygens found is in excess of the number obtained from a simple stoichiometric prediction. In addition, the aluminum avoidance principle, which states that links between (formula presented) tetrahedra are absent or rare, is found to be violated. Defects such as two-fold rings and five-fold coordinated silicon atoms are found in comparable proportions in both liquids. However, in the calcium aluminosilicate melt, a larger proportion of oxygen atoms are three-fold coordinated. In addition, fivefold coordinated aluminum atoms are observed. Finally evidence of creation and anihilation of nonbridging oxygens is observed, with these oxygens being mostly connected to Si tetrahedra.

Original languageEnglish (US)
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume64
Issue number22
DOIs
StatePublished - Jan 1 2001

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Silicates
Molecular dynamics
Molten materials
Structural properties
calcium
Aluminosilicates
silicates
Oxygen
molecular dynamics
Calcium
tetrahedrons
proportion
Computer simulation
oxygen
Aluminum
Atoms
aluminum
simulation
avoidance
atoms

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

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title = "Structural properties of molten silicates from ab initio molecular-dynamics simulations: Comparison between (formula presented) and (formula presented)",
abstract = "We present the results of first-principles molecular-dynamics simulations of molten silicates, based on the density functional formalism. In particular, the structural properties of a calcium aluminosilicate (formula presented) melt are compared to those of a silica melt. The local structures of the two melts are in good agreement with the experimental understanding of these systems. In the calcium aluminosilicate melt, the number of nonbridging oxygens found is in excess of the number obtained from a simple stoichiometric prediction. In addition, the aluminum avoidance principle, which states that links between (formula presented) tetrahedra are absent or rare, is found to be violated. Defects such as two-fold rings and five-fold coordinated silicon atoms are found in comparable proportions in both liquids. However, in the calcium aluminosilicate melt, a larger proportion of oxygen atoms are three-fold coordinated. In addition, fivefold coordinated aluminum atoms are observed. Finally evidence of creation and anihilation of nonbridging oxygens is observed, with these oxygens being mostly connected to Si tetrahedra.",
author = "Magali Benoit and Simona Ispas and Mark Tuckerman",
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T1 - Structural properties of molten silicates from ab initio molecular-dynamics simulations

T2 - Comparison between (formula presented) and (formula presented)

AU - Benoit, Magali

AU - Ispas, Simona

AU - Tuckerman, Mark

PY - 2001/1/1

Y1 - 2001/1/1

N2 - We present the results of first-principles molecular-dynamics simulations of molten silicates, based on the density functional formalism. In particular, the structural properties of a calcium aluminosilicate (formula presented) melt are compared to those of a silica melt. The local structures of the two melts are in good agreement with the experimental understanding of these systems. In the calcium aluminosilicate melt, the number of nonbridging oxygens found is in excess of the number obtained from a simple stoichiometric prediction. In addition, the aluminum avoidance principle, which states that links between (formula presented) tetrahedra are absent or rare, is found to be violated. Defects such as two-fold rings and five-fold coordinated silicon atoms are found in comparable proportions in both liquids. However, in the calcium aluminosilicate melt, a larger proportion of oxygen atoms are three-fold coordinated. In addition, fivefold coordinated aluminum atoms are observed. Finally evidence of creation and anihilation of nonbridging oxygens is observed, with these oxygens being mostly connected to Si tetrahedra.

AB - We present the results of first-principles molecular-dynamics simulations of molten silicates, based on the density functional formalism. In particular, the structural properties of a calcium aluminosilicate (formula presented) melt are compared to those of a silica melt. The local structures of the two melts are in good agreement with the experimental understanding of these systems. In the calcium aluminosilicate melt, the number of nonbridging oxygens found is in excess of the number obtained from a simple stoichiometric prediction. In addition, the aluminum avoidance principle, which states that links between (formula presented) tetrahedra are absent or rare, is found to be violated. Defects such as two-fold rings and five-fold coordinated silicon atoms are found in comparable proportions in both liquids. However, in the calcium aluminosilicate melt, a larger proportion of oxygen atoms are three-fold coordinated. In addition, fivefold coordinated aluminum atoms are observed. Finally evidence of creation and anihilation of nonbridging oxygens is observed, with these oxygens being mostly connected to Si tetrahedra.

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