First-principles study of the geometrical and electronic structures of Inn (n = 2-16) clusters

The lowest-energy structures and electronic properties of indium clusters have been systematically investigated by using density-functional theory with the generalized gradient approximation (GGA). Our calculations show that the lowest-energy structure for the n atom cluster can be obtained by capping an atom on the structure of the n − 1 atom cluster. With increasing cluster size, we find that indium clusters tend to adopt compact structures. The calculated results on the average binding energy, second-order difference of cluster energies, the vertical ionization potentials as well as the HOMO-LUMO gaps of the Inn (n = 2-l6) clusters indicate that the relative stability of In2,In4,In6,In8,In10 and In13 is stronger than that of other size clusters. On the other hand, stability of In clusters can also be explained according to the average slope of the average binding energy curve varying with cluster size n. Moreover, the stability is more prominent at n = 8 and 13.