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

• Published in: Journal of nuclear materials Vol. 486; pp. 122 - 128
• Main Authors: Petersen, B.A., Liu, B., Weber, W.J., Zhang, Y.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2017; Elsevier BV; Elsevier
• Subjects: ab initio MD; Charge transfer; Correlation analysis; Crystallography; Displacement; Energy; Heat transfer; Magnesium oxide; MgO; Molecular dynamics; Molecular physics; NUCLEAR FUEL CYCLE AND FUEL MATERIALS; Oxides; radiation damage; Recoil; Studies
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2017.01.020

Low-energy recoil events in MgO are studied using ab intio molecular dynamics simulations to reveal the dynamic displacement processes and final defect configurations. Threshold displacement energies, Ed, are obtained for Mg and O along three low-index crystallographic directions, [100], [110], and [111]. The minimum values for Ed 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. 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.