Non-crystalline structures in the growth of silver nanoclusters

The growth of nanometer-size free Ag clusters is studied by Molecular Dynam ics simulations. The morphology transition from the icosahedron at the magi c size of N = 55 atoms to the Marks truncated decahedron at N = 75 is analy zed in details, in order to single out kinetic trapping and entropic effect s. At very low T, the cluster is kinetically trapped in an icosahedral stru cture, At intermediate T the transition takes place sharply at N similar or equal to 65. At higher T, the transition is smeared out and finally, aroun d 550 K no transition is found because the 75 decahedron is melted.