Comparative study of cascade damage in Fe simulated with recent potentials

Considerable quantitative uncertainty has remained regarding the amount and structure of defects produced in molecular dynamics simulations of collision cascades in Fe. The problem is most likely related to the description of interstitial energetics in the interatomic potentials. Three potentials have recently been developed for Fe, which, even though they have different physical motivations and functional forms, describe the interstitial energetics well. Using these potentials, we simulate recoil collision cascades in Fe in the recoil energy range 0.5-20 keV. Prior to the cascade simulations a realistic high-energy repulsive part was added to two of the potentials, adjusting the fit to reproduce the experimentally obtained threshold displacement energies. The results show that the total Frenkel pair production, as predicted by the three potentials, is the same within the statistical uncertainty, but also that some differences remain in the fraction of clustered defects. However, these differences are smaller than those predicted by previous potentials. (c) 2007 Elsevier B.V. All rights reserved.