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Title: Ab initio molecular dynamics simulations of low energy recoil events in MgO

In this paper, low-energy recoil events in MgO are studied using ab initio molecular dynamics simulations to reveal the dynamic displacement processes and final defect configurations. Threshold displacement energies, E d, are obtained for Mg and O along three low-index crystallographic directions, [100], [110], and [111]. The minimum values for E d are found along the [110] direction consisting of the same element, either Mg or O atoms. Minimum threshold values of 29.5 eV for Mg and 25.5 eV for O, respectively, are suggested from the calculations. For other directions, the threshold energies are considerably higher, 65.5 and 150.0 eV for O along [111] and [100], and 122.5 eV for Mg along both [111] and [100] directions, respectively. These results show that the recoil events in MgO are partial-charge transfer assisted processes where the charge transfer plays an important role. Finally, there is a similar trend found in other oxide materials, where the threshold displacement energy correlates linearly with the peak partial-charge transfer, suggesting this behavior might be universal in ceramic oxides.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [2]
  1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering
  2. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 486; Journal ID: ISSN 0022-3115
Publisher:
Elsevier
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Nuclear Energy (NE). Nuclear Energy University Program (NEUP)
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; MgO; ab initio MD; radiation damage
OSTI Identifier:
1340466
Alternate Identifier(s):
OSTI ID: 1396872