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 language | English |
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Pages (from-to) | 624-632 |
Number of pages | 9 |
Journal | Physics and Chemistry of Minerals |
Volume | 26 |
Issue number | 8 |
DOIs | |
Publication status | Published - Sep 1 1999 |
Keywords
- Al-O-Al linkage
- Anorthite
- Ca position
- Molecular dynamics simulation
- P1-I1 phase transition
ASJC Scopus subject areas
- Materials Science(all)
- Geochemistry and Petrology