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Title: Temperature effects on atomic pair distribution functions of melts

Using molecular dynamics simulations, we investigate the temperature-dependent evolution of the first peak position/shape in pair distribution functions of liquids. For metallic liquids, the peak skews towards the left (shorter distance side) with increasing temperature, similar to the previously reported anomalous peak shift. Making use of constant-volume simulations in the absence of thermal expansion and change in inherent structure, we demonstrate that the apparent shift of the peak maximum can be a result of the asymmetric shape of the peak, as the asymmetry increases with temperature-induced spreading of neighboring atoms to shorter and longer distances due to the anharmonic nature of the interatomic interaction potential. These findings shed light on the first-shell expansion/contraction paradox for metallic liquids, aside from possible changes in local topological or chemical short-range ordering. The melts of covalent materials are found to exhibit an opposite trend of peak shift, which is attributed to an effect of the directionality of the interatomic bonds.
Authors:
;  [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [3] ;  [4]
  1. Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)
  2. I. Physikalisches Institut IA, RWTH Aachen University, Aachen 52056 (Germany)
  3. (China)
  4. Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
Publication Date:
OSTI Identifier:
22255139
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DISTRIBUTION FUNCTIONS; INTERACTIONS; LIQUIDS; MOLECULAR DYNAMICS METHOD; SIMULATION; TEMPERATURE DEPENDENCE; THERMAL EXPANSION; VISIBLE RADIATION