Implementation of a new Fe-He three-body interatomic potential for molecular dynamics simulations

A recently developed interatomic potential for He-Fe interactions includes a three-body term to stabilize the interstitial He defect in the tetrahedral position in the Fe bcc matrix and provides simultaneous agreement with the forces and energies of different atomic configurations as computed by first principles. This term makes a significant contribution to the static and dynamic properties of He in Fe. The implementation of this potential for atomistic simulations using molecular dynamics (MD) presented certain challenges which are discussed here to facilitate its further use in materials research, particularly to investigate the behavior of iron-based alloys that may be employed in fusion energy systems. Detailed results of an MD study comparing the new potential and alternate He-Fe pair potentials with different iron matrix potentials have been presented elsewhere to illustrate the impact of the He-Fe potential on He diffusion, helium clustering and the dynamics of He-vacancy clusters.