Compression mechanism of cubic silica sodalite Si12O24 : a first principles study of the Im3-over-bar-m to I4-over-bar-3m phase transition

Knorr, K., Winkler, B. and Milman, V. (2001) Compression mechanism of cubic silica sodalite Si12O24 : a first principles study of the Im3-over-bar-m to I4-over-bar-3m phase transition Zeitschrift Fur Kristallographie, 216 (9). pp. 495-500. DOI 10.1524/zkri.216.9.495.20347.

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Abstract

The high pressure behaviour of cubic silica sodalite has been investigated by ab initio calculations, based on density functional theory. The experimentally observed phase transition from the fully-expanded ideal sodalite framework (space group Im(3) over barm) to a collapsed framework with space group I(4) over bar 3m could be successfully reproduced to appear at 0.12 GPa. This transition is discontinuous. The mechanism of the transition can be understood in terms of a tilt of the framework and of deformations of the SiO4-tetrahedra. Discontinuities of the enthalpy, cell volume, Si-O bond lengths and angles at 1.15 and 3.01 GPa point at further possible pressure-induced iso-symmetric phase transitions in the space group I(4) over bar 3m.

Document Type: Article
Keywords: total-energy calculations high-pressure pseudopotentials behavior systems
Research affiliation: Kiel University
DOI etc.: 10.1524/zkri.216.9.495.20347
ISSN: 0044-2968
Date Deposited: 02 Feb 2012 07:27
Last Modified: 08 Oct 2012 10:39
URI: http://eprints.uni-kiel.de/id/eprint/16294

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