THE MINIMUM-ENERGY STRUCTURE OF NANOMETER-SCALE GOLD CLUSTERS

We report results of experiments in which gold clusters with controlle d diameters ranging from 1nm to 20nm are grown in a gas aggregation re actor and are subsequently melted and slowly cooled in the gas phase. These clusters are soft landed on thin carbon films and their structur e determined by means of HRTEM. All of the clusters down to the smalle st whose lattice fringes could be resolved (N almost-equal-to 405) are single fcc crystals. MD calculations using an EAM potential for gold predict that the fcc motif seen in these experiments may indeed be the minimum-energy structure for gold clusters containing more than a few hundred atoms.