HIGH-PRESSURE PHASES OF SIO2 USING LOCAL-DENSITY AND GENERALIZED-GRADIENT APPROXIMATIONS

Citation
Jk. Dewhurst et al., HIGH-PRESSURE PHASES OF SIO2 USING LOCAL-DENSITY AND GENERALIZED-GRADIENT APPROXIMATIONS, Physical review. B, Condensed matter, 55(17), 1997, pp. 11003-11005
Citations number
20
Categorie Soggetti
Physics, Condensed Matter
ISSN journal
01631829
Volume
55
Issue
17
Year of publication
1997
Pages
11003 - 11005
Database
ISI
SICI code
0163-1829(1997)55:17<11003:HPOSUL>2.0.ZU;2-K
Abstract
Plane-wave calculations using the local-density approximation (LDA) ar e compared with those using the generalized-gradient approximation (GG A) in various high-pressure polymorphs of silica. The GGA gives lower cohesive energies and bulk modulii than the LDA but larger equilibrium unit-cell volumes. The cellular structure of the high-pressure post-s tishovite (CaCl2) phase is examined and suggested having a slightly la rger bulk modulus than stishovite. Trends in properties of the various phases are nearly similar using both approaches.