Molecular-dynamics simulations show that the coalescence of iron nanoclusters (${\mathrm{Fe}}_{\mathrm{N}}+{\mathrm{Fe}}_{\mathrm{N}}\to {\mathrm{Fe}}_{2\mathrm{N}}$, where up to $2\mathrm{N}=\mathrm{10\hspace{0.17em}000}$ atoms, or a diameter of $6\mathrm{nm}$, has been studied) occurs at the temperatures lower than the cluster melting point, and that the difference between coalescence and melting temperatures increases with decreasing cluster size. Thus, the temperature at which small metal nanoclusters are observed to coalescence, e.g., in the experimental growth of carbon nanotubes, is not the same as their melting point.

• Received 26 February 2004

DOI:https://doi.org/10.1103/PhysRevB.70.075416