An improved interatomic potential for xenon in UO2: A combined density functional theory/genetic algorithm approach

Alexander E. Thompson, Bryce Meredig, Christopher M Wolverton

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

We have created an improved xenon interatomic potential for use with existing UO2 potentials. This potential was fit to density functional theory calculations with the Hubbard U correction (DFT + U) using a genetic algorithm approach called iterative potential refinement (IPR). We examine the defect energetics of the IPR-fitted xenon interatomic potential as well as other, previously published xenon potentials. We compare these potentials to DFT + U derived energetics for a series of xenon defects in a variety of incorporation sites (large, intermediate, and small vacant sites). We find the existing xenon potentials overestimate the energy needed to add a xenon atom to a wide set of defect sites representing a range of incorporation sites, including failing to correctly rank the energetics of the small incorporation site defects (xenon in an interstitial and xenon in a uranium site neighboring uranium in an interstitial). These failures are due to problematic descriptions of Xe-O and/or Xe-U interactions of the previous xenon potentials. These failures are corrected by our newly created xenon potential: our IPR-generated potential gives good agreement with DFT + U calculations to which it was not fitted, such as xenon in an interstitial (small incorporation site) and xenon in a double Schottky defect cluster (large incorporation site). Finally, we note that IPR is very flexible and can be applied to a wide variety of potential forms and materials systems, including metals and EAM potentials.

Original languageEnglish (US)
Article number105501
JournalJournal of Physics Condensed Matter
Volume26
Issue number10
DOIs
StatePublished - Mar 12 2014

Keywords

  • density functional theory
  • molecular dynamics
  • potential fitting
  • UO

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Science(all)
  • Medicine(all)

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