A simulation was made of a screw dislocation in model crystals of various sizes. The number of atom rows in the crystal was 360 to 1400, and a Lennard-Jones (12-6) interatomic potential truncated at third-nearest neighbors was adopted. The ordinary relaxation method was used to obtain the stable configuration of atoms in the crystal. It was found that the dislocation split into two Shockley partials, and that the configuration of the partials depended upon the boundary condition of the crystal surface. A modified boundary condition was proposed in order to control the effect of the surface. The split dislocations were able to exist stably when their separation was within a certain range which could be understood by considering the balance of three forces: the interaction force between partials, the force due to stacking faults and the image force arising from the crystal surface. By taking the limiting value of the separation distance for a crystal of infinite size, the stacking-fault energy was estimated to be 1.09mJ/m2.

Simulation of Dislocation Configuration in Rare Gas Crystals. Y.Kogure, T.Tsuchiya, Y.Hiki: Journal of the Physical Society of Japan, 1987, 56[3], 989-98