Molecular dynamics calculations were performed to study the melting evolution, atomic diffusion and vibrational behavior of body-centred cubic metal vanadium nanoparticles with the number of atoms ranging from 537 to 28475 (diameters of 2 to 9nm). The interactions between atoms were described using an analytic embedded-atom method. The obtained results revealed that the melting temperatures of nanoparticles were inversely proportional to the reciprocal of the nanoparticle size, and were in good agreement with the predictions of the thermodynamic liquid-drop model. The melting process could be described as occurring in two stages, firstly the stepwise pre-melting of the surface layer with a thickness of 2 to 3 times the perfect lattice constant, and then the abrupt overall melting of the whole cluster. The heats of fusion of nanoparticles were also inversely proportional to the reciprocal of the nanoparticle size. The diffusion was mainly localized to the surface layer at low temperatures and increased with the reduction of nanoparticle size, with the temperature being held constant. The radial mean square vibration amplitude was developed to study the anharmonic effect on surface shells.

Melting Evolution and Diffusion Behavior of Vanadium Nanoparticles. W.Hu, S.Xiao, J.Yang, Z.Zhang: European Physics Journal B, 2005, 45[4], 547-54