A numerical study upon the atomistic mechanisms of rapid diffusion in nanoclusters

► The rapid diffusion in nanoparticles were reproduced by MD simulations. ► The atomistic diffusion mechanism in a metal cluster is Surface Peeling Mechanism. ► In contrast, the diffusion mechanism in an alkali halide cluster is Vacancy Mechanism. ► The vacancy formation energy of metal clusters increases as their size decreases, while that of alkali halides decreases. ► This opposite trend is a reason for the onset of the totally different mechanisms.