Developing empirical potentials from ab initio simulations for modelling silicate glasses
Résumé
We have parameterized empirical potentials for molecular dynamics (MD) simulations of
multi-component silicate glasses. The main motivation has been to improve predictions of
static properties like elastic moduli and dynamic properties like vibrational density of states
(VDOS) that MD simulations have generally not been able to estimate correctly, while still
using a simple functional form for computational efficiency.
Our approach has been to fit the potentials to data extracted from accurate first principles
calculations to predict both the static and dynamic properties correctly, by explicitly incor-
porating the radial distribution function (RDF) and the VDOS into the cost function of the
fitting scheme. The current optimization scheme is an extension of a recent work using as
input only the structural data from the ab initio simulations, and which has been applied in
the past to obtain a reliable potential for amorphous silica [1,2].
The newly developed potentials will be used to study the elastic response of multi-component
oxide glasses to external stimuli such as high temperatures, high pressures and high strains,
and their deformation modes under different loading conditions.
A. Carré, J. Horbach, S. Ispas, W. Kob, Europhys. Lett. 82 (2008) 17001.
A. Carré, S. Ispas, J. Horbach, W. Kob, Comput. Mater. Sci. 124 (2016) 323