INTERATOMIC POTENTIALS FOR ELASTICALLY ISOTROPIC CRYSTALS

We introduce a simple approach to fitting interatomic potentials to re present elastically isotropic solids, in order to make direct comparis ons with the predictions of isotropic linear elasticity. The potential s are of the Finnis-Sinclair type and are parametrized to fit Au and A g. Under uniaxial loading, it was shown that the solids modelled emplo ying the 'elastically isotropic' potentials remain elastically isotrop ic for strains of 0.5% or less. The properties of the (001), {011} and (111) surfaces were determined and compared with those of elastically anisotropic An and Ag. It was also found that the surface energy anis otropy is lower in solids modelled employing 'elastically isotropic' p otentials than in those represented by elastically anisotropic potenti als.