Computer modeling of natural silicate melts: what can we learn from ab initio simulations

Abstract

The structural and dynamical properties of four silicate liquids (silica, rhyolite, a model basalt and enstatite) are evaluated by ab initio molecular dynamics simulation using the density functional theory and are compared with classical simulations using a simple empirical force field. For a given composition, the structural parameters of the simulated melt vary little between the two calculations (ab initio versus empirical) and are in satisfactory agreement with structure data available in the literature. In contrast, ionic diffusivities and atomic vibration motions are found to be more sensitive to the details of the interactions. Furthermore, it is pointed out that the electronic polarization, as evaluated by the ab initio calculation, contributes significantly to the intensity of the infrared absorption spectra of molten silicates, a spectral feature which cannot be reproduced using nonpolarizable force field. However the vibration modes of TO4 species and some structural details are not accurately reproduced by our ab initio calculation, shortcomings which need to be improved in the future.

87 pages, 16 figures

References in corpus (2)

• Theoretical and experimental evidence for a post-perovskite phase of MgSiO3 in Earth's D" layer
• First principles study of density, viscosity, and diffusion coefficients of liquid MgSiO3 at conditions of the Earth's deep mantle

Cited by in corpus (6)

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• Carbon dioxide in silicate melts: A molecular dynamics simulation study
• Density Functional Modeling and Total Scattering Analysis of the Atomic Structure of a Quaternary CaO-MgO-Al2O3-SiO2 (CMAS) Glass: Uncovering the Local Environment of Magnesium
• Ab initio based polarizable force field generation and application to liquid silica and magnesia
• Electronic redistribution around oxygen atoms in silicate melts by ab initio molecular dynamics simulation