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arXiv · 0804.2660

Molecular dynamics computer simulation of amorphous silica under high pressure

Juergen Horbach
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Abstract

The structural and dynamic properties of silica melts under high pressure are studied using molecular dynamics (MD) computer simulation. The interactions between the ions are modeled by a pairwise-additive potential, the so-called CHIK potential, that has been recently proposed by Carre et al. The experimental equation of state is well-reproduced by the CHIK model. With increasing pressure (density), the structure changes from a tetrahedral network to a network containing a high number of five- and six-fold Si-O coordination. In the partial static structure factors, this change of the structure with increasing density is reflected by a shift of the first sharp diffraction peak towards higher wavenumbers q, eventually merging with the main peak at densities around 4.2 g/cm^3. The self-diffusion constants as a function of pressure show the experimentally-known maximum, occurring around a pressure of about 20 GPa.

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Juergen Horbach. 2008-04-16. Molecular dynamics computer simulation of amorphous silica under high pressure. https://doi.org/10.1088/0953-8984%2F20%2F24%2F244118

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