The compressibility and high pressure structure of diopside from first principles simulation

Walker, A. M. and Tyer, R. and Bruin, R. P. and Dove, M. T. (2008) The compressibility and high pressure structure of diopside from first principles simulation. Physics and Chemistry of Minerals, 35 (7). pp. 359-366. ISSN 0342-1791 (Print) 1432-2021 (Online) DOI 10.1007/s00269-008-0229-3

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Abstract

The structure of diopside (CaMgSi2O6) has been calculated at pressures between 0 and 25 GPa using the planewaves and pseudopotentials approach to density functional theory. After applying a pressure correction of 4.66 GPa to allow for the under-binding usually associated with the generalized gradient approximation, cell parameters are in good agreement with experiment. Fitting to the third-order Birch–Murnaghan equation of state yields values of 122 GPa and 4.7 for the bulk modulus and its pressure derivative. In addition to cell parameters, our calculations provide all atomic positional parameters to pressures considerably beyond those currently available from experiment. We have analyzed these data in terms of polyhedral rigidity and regularity and find that the most compressible Ca polyhedron becomes markedly less anisotropic above 10 GPa.

Item Type: Article
Uncontrolled Keywords: 08AREP IA56 2008 P
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Physics and Chemistry of Minerals
Volume: 35
Page Range: pp. 359-366
Identification Number: 10.1007/s00269-008-0229-3
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:04
Last Modified: 23 Jul 2013 10:08
URI: http://eprints.esc.cam.ac.uk/id/eprint/777

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