The MS-Q Force Field for Ceramics; Application to the QuartzStishovite Phase Transition and to Silica Glass
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by Ersan Demiralp, Tahir Cagin, William A. Goddard Iii
http://www.cacr.caltech.edu/ASAP/onlineresources/publications/msqsio.ps.gz
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Abstract:
In order to predict phase transitions in ceramics and minerals from molecular dynamics (MD) simulations, we have developed a new strategy for force fields in which the charges are allowed to readjust instantaneously to the atomic configurations. These charges are calculated using the charge equilibration (QEq) method. In addition to electrostatics, a two-body Morse stretch potential is included to account for short-range nonelectrostatic interactions; however, no three-body terms are used. This MS-Q potential is applied herein to SiO 2 where we find that it describes well four-coordinate and six-coordinate systems (such as quartz and stishovite), silica glass, and the pressure induced phase transition from quartz to stishovite.
Citations
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