Molecular dynamics simulation of the effect of the Al-O-Al linkage on the P1-I1 phase transition of anorthite

A. Miyake, K. Kawamura, M. Kitamura

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3 Citations (Scopus)

Abstract

Molecular dynamics (MD) simulations of the influence of the Al-O-Al linkage on the P1-I1 phase transition of pure anorthite (An) were carried out using two different types of structures with fully ordered (FO) and partially disordered (PD) arrangements of Al/Si in tetrahedral sites. Discontinuous changes in unit cell volumes and structure factors at the transition temperature were observed in FO-An but not in PD-An. These results show that the orders of the transitions of FO-An and PD-An are first and non-first, respectively. In both structures, the motions of the Ca atoms and the framework are strongly correlated with each other during the transition and Ca atoms dominate the system. Since high-temperature X-ray studies have shown that the transition of natural anorthite is non-first order, it is suggested that the natural anorthite has a partially disordered arrangement of Al and Si atoms.

Original languageEnglish
Pages (from-to)624-632
Number of pages9
JournalPhysics and Chemistry of Minerals
Volume26
Issue number8
DOIs
Publication statusPublished - Sep 1999
Externally publishedYes

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Keywords

  • Al-O-Al linkage
  • Anorthite
  • Ca position
  • Molecular dynamics simulation
  • P1-I1 phase transition

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Materials Science(all)

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