Stacking fault widths, energies and dislocation core structures

In light of the present distinction between the theoretical stacking fault energy and a similar parameter employed to indicate the experimental stacking fault width, the theoretical stacking fault energy in fcc lattices is shown to (1) have little value as a fitting parameter for empirical interatomic potential, and (2) to be of limited value as a guide to dislocation core structures obtained from computer simulation studies. In bcc structures, where similar pair potentials display very different core structures, the degree of core dissociation in a lattice has limited correlation with a generalized theoretical stacking fault energy. The Peierls stress is noted to be sensitive to the form of the pair potential.