Encoding electronic structure information in potentials for multi-scale simulations: SiO2

Wuming Zhu, D. E. Taylor, A. R. Al-Derzi, K. Runge, S. B. Trickey, Ju Li, Ting Zhu, S. Yip

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Potentials generally used in molecular dynamics (MD) simulation of SiO2 properties customarily are calibrated to a combination of computed molecular electronic structure data and experimental crystalline data. The present study tests parametrization to data from high-level, first-principles electronic structure calculations alone. The issue is crucial to the success of multi-scale simulations. They require a consistent embedding of the so-called quantum mechanical region (the region in which the forces come from gradients of quantum mechanical total energies) in a classical inter-ionic potential region. The evident challenge is generation of a quantum mechanically consistent parametrization. A simple probe of the issue is to see how parametrization solely from first-principles data influences the simulation outcomes. We parametrized a widely used form of effective inter-ionic potential for SiO2 and did MD simulations of tensile failure in a 72 formula unit SiO2 nanorod. Separate parametrizations were done to high quality calculated data for H4SiO4 and H6Si2O7 clusters and for α-quartz. The differing parametrizations yield quantitative differences in the prediction of the yield strength and even semi-qualitative differences in the system behavior in that region. Some superficially similar parametrizations do not even provide a stable T = 0 K configuration. These differences highlight the crucial distinction between potential parametrization aimed at replacing realistic quantum mechanical forces entirely in an MD calculation versus a parametrization aimed at embedding an explicitly QM region.

Original languageEnglish (US)
Pages (from-to)340-349
Number of pages10
JournalComputational Materials Science
Volume38
Issue number2
DOIs
StatePublished - Dec 1 2006
Externally publishedYes

Keywords

  • Inter-atomic potentials
  • Multi-scale simulations
  • Silica simulations

ASJC Scopus subject areas

  • Computer Science(all)
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Computational Mathematics

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