The annealing kinetics of vacancies in finite monolayer-patches of several thousand particles were studied, by means of molecular dynamics techniques, for 3 central-force interactions. These were the nearest-neighbor piece-wise linear force potential, the Lennard-Jones potential and the similar 8-4 potential. The simplest behavior which was observed was diffusion of the vacancies to the nearest basins of attraction. These were the edges, or a larger concentration of vacancies. In the latter case, a void was created. The voids then migrated to the next attractor, to form larger voids, until all of the vacancies had been annealed. A rapid dislocation-mediated healing process, which removed most of the vacancies (with the dislocations annealing out), could be observed under long-range inter-particle interactions. The presence of mobile vacancies and applied pressure also favored the phenomenon. Dislocation-mediated healing could occur well below the self-diffusion temperature for vacancies. A reversible, void to dislocation-dipole, conversion was observed, together with some small vacancy clusters, in systems which exhibited both annealing processes.

Z.Zhou, B.Joós: Surface Science, 1995, 323, 311-22