TY - JOUR

T1 - The influence of dipole polarisation on threshold displacement energies in UO2

AU - Bishop, Clare L.

AU - Murphy, Samuel T.

AU - Rushton, Michael J. D.

AU - Grimes, Robin W.

PY - 2012/3/1

Y1 - 2012/3/1

N2 - Molecular dynamics simulations of radiation damage in nuclear materials have traditionally been performed using rigid ion empirical potential models. The inclusion of dipole polarisability via the shell model offers the possibility to incorporate more of the underlying physics into simulations of radiation damage via cascade simulations. Here we assess the impact of dipole polarisability on the evolution of radiation damage in UO2 by performing molecular dynamics simulations to determine the threshold displacement energies using both a standard rigid ion potential and the equivalent model including dipole polarisability. The inclusion of dipole polarisability reduces the threshold displacement energies by 20-30% relative to the rigid ion model, suggesting a significant increase in the number of defects created during the collisional phase of the cascade. However, a reduction in the activation energies for migration due to inclusion of polarisability may increase the rate of subsequent interstitial-vacancy recombination. The overall level of radiation damage will, therefore, be determined by the relative effectiveness of these two opposing processes. (C) 2011 Elsevier B.V. All rights reserved.

AB - Molecular dynamics simulations of radiation damage in nuclear materials have traditionally been performed using rigid ion empirical potential models. The inclusion of dipole polarisability via the shell model offers the possibility to incorporate more of the underlying physics into simulations of radiation damage via cascade simulations. Here we assess the impact of dipole polarisability on the evolution of radiation damage in UO2 by performing molecular dynamics simulations to determine the threshold displacement energies using both a standard rigid ion potential and the equivalent model including dipole polarisability. The inclusion of dipole polarisability reduces the threshold displacement energies by 20-30% relative to the rigid ion model, suggesting a significant increase in the number of defects created during the collisional phase of the cascade. However, a reduction in the activation energies for migration due to inclusion of polarisability may increase the rate of subsequent interstitial-vacancy recombination. The overall level of radiation damage will, therefore, be determined by the relative effectiveness of these two opposing processes. (C) 2011 Elsevier B.V. All rights reserved.

U2 - 10.1016/j.nimb.2011.11.023

DO - 10.1016/j.nimb.2011.11.023

M3 - Erthygl

VL - 274

SP - 195

EP - 199

JO - Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

JF - Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

SN - 0168-583X

ER -