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Title: Topological ordering in liquid UO 2

A molecular dynamics model of liquid UO2 that is in good agreement with recent high-energy x-ray diffraction data has been analyzed using the Bhatia–Thornton formalism. A pre-peak appears in the topological structure factor S NN(Q) at Q = 1.85(1)Å-1 which is not present in the more common, element specific Faber–Ziman partial structure factors. A radical Voronoi tessellation of the 3D molecular dynamics model shows the presence of a wide distribution of clusters, consistent with presence of highly mobile oxygen atoms. However, 4-fold Voronoi polyhedra (n 4) are found to dominate the structure and the majority of clusters can be described by the distribution n 3 ≤ n 4 ≥ n 5. It is argued that an open network of 4-fold Voronoi polyhedra could explain the origin of the pre-peak in S NN(Q) and the topological ordering observed in liquid UO2.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States); Stony Brook Univ., NY (United States)
  3. Materials Development, Inc., Arlington Heights, IL (United States)
  4. Stony Brook Univ., NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
OSTI Identifier:
1248943
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physics. Condensed Matter; Journal Volume: 28; Journal Issue: 1
Publisher:
IOP Publishing
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS