Theoretical study of the structure and energetics of silver clusters

Using four different model potentials for silver, we have calculated the structural and energetic properties of the three energetically lowest isomers of Ag-N clusters. With two versions of the Gupta potential, we have considered N up to 150, whereas clusters with N up to 60 were studied with two different embedded-atom potentials. The results are compared with more accurate theoretical results for small AgN clusters and with experimental trapped ion electron diffraction data. It is found that the different potentials lead to related structural patterns, but the structures differ in details. In particular, the model potentials tend to prefer a decahedral growth, whereas experiment suggests icosahedral growth. Moreover, a comparison with related results for other metal clusters is made, too. Here, significant differences to gold clusters are found, and the largest similarity is found when comparing with copper clusters. Clusters of nickel seem to be less similar than copper but more than gold. To quantify these comparisons, various specifically developed descriptors are applied.