Dresden 2003 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 37: Critical phenomena and phase transitions II
DY 37.1: Vortrag
Mittwoch, 26. März 2003, 16:30–16:45, G\"OR/229
Molecular dynamics simulations of crystalline silica — •Daniel Herzbach1, Martin H. Müser2, and Kurt Binder1 — 1Institut für Physik, WA 331, Universität Mainz, 55099 Mainz, Germany — 2Department of Applied Mathematics, University of Western Ontario, London N6A 5B7, Canada
We compare structural, thermal, and dynamic properties of pure silica,
SiO2, by simulations using two different model potentials, namely the
BKS potential suggested by van Beest, Kramer, and van Santen (BKS) and the
fluctuating charge potential by Demiralp, Cagin, and Goddard (DCG), Phys.
Rev. Lett. 82, 1708 (1999).
While BKS reproduces many thermomechanical properties of different
polymorphs rather accurately, it also shows some qualitatively wrong trends
for instance in the alpha to beta quarz transition.
In the DCG potential the effective charges of atoms adjust
themselves as a function of the chemical environment. Therefore it
can be seen as a compromise between quantum chemical and pseudo potential
approaches.
We show that the DCG potential can remedy some artefacts arising
in simulations with BKS, but it fails to improve on others.