Influence of the interatomic potentials on molecular dynamics simulations of displacement cascades

Molecular dynamics (MD) is a powerful tool to study the displacement cascad es initiated by the neutrons when they interact with matter. Key components of this technique are the interatomic potentials which model the binding o f the different constitutive atoms. There exist many interatomic potentials dedicated to alpha-Fe and we have tested three of them for the study of ra diation damage. We have found that the primary damage is potential sensitiv e. From our study, it appears that some characteristics of the potentials, not always considered, can be correlated to the type of damage produced by displacement cascades. The repulsive part of the potential has a strong inf luence on the cascade morphology. Moreover, equilibrium properties such as the atoms mean square displacements, the vacancy migration and vacancy-vaca ncy binding energies also appear to have some influence and should be inves tigated carefully when simulating radiation damage. It is therefore very im portant to use extreme care when trying to obtain quantitative results from MD simulations. (C) 2000 Elsevier Science B.V. All rights reserved.