Classical molecular dynamics simulations were employed to estimate the energy required to form vacancy in unsupported nanometre-sized spherical particles of Au and Cu. Their dynamics was also investigated to corroborate the vacancy formation energy estimates and to characterize its relationship with particle size. It was shown that the particle was a strongly inhomogeneous system. The generation of vacancies at random in its interior permits to identify three different regions characterized by as much different values of vacancy formation energy. The bulk-like region exhibits values equal to the ones pertaining to bulk systems, whereas the vacancy formation energy increases as the surface layer was approached. It follows that the vacancy formation energy was slightly higher in nanometre-sized particles than in bulk.

Energy of Formation and Dynamics of Vacancies in Nanometre-Sized Crystalline Au and Cu Systems. F.Delogu: Materials Chemistry and Physics, 2009, 115[1], 361-6