Warning! Note that elemental potentials taken from alloy descriptions may not work well for the pure species. This is particularly true if the elements were fit for compounds instead of being optimized separately. As with all interatomic potentials, please check to make sure that the performance is adequate for your problem.
Citation: J. Wallenius, P. Olsson, and C. Lagerstedt (2005), "Relation between thermal expansion and interstitial formation energy in pure Fe and Cr", Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 228(1-4), 122-125. DOI: 10.1016/j.nimb.2004.10.032.
Abstract: By fitting a potential of modified Finnis–Sinclair type to the thermal expansion of ferromagnetic Fe and paramagnetic Cr, stability of the <110> self-interstitial atom is obtained. The resulting potentials are relatively hard, yielding high SIA formation energies. Less hard potentials give lower interstitial formation energy, but predict too small thermal expansion. We also show that the formation energy of the <111> SIA depends on distances in-between the 2nd and 3rd neighbour. By raising the value of the pair potential in this region, the energy difference with respect to the <110> configuration calculated with VASP in the PAW approximation can be reproduced.