First-principles study of intermediate size silver clusters: Shape evolution and its impact on cluster properties

Low-energy isomers of Ag-N clusters are studied within gradient-corrected density functional theory over the size range of N=9-20. The candidate conformations are drawn from an extensive structural database created in a recent exploration of Cu-N clusters [M. Yang , J. Chem. Phys. 124, 24308 (2006)]. Layered configurations dominate the list of the lowest-energy isomers of Ag-N for N < 16. The most stable structures for N > 16 are compact with quasispherical shapes. The size-driven shape evolution is similar to that found earlier for Na-N and Cu-N. The shape change has a pronounced effect on the cluster cohesive energies, ionization potentials, and polarizabilities. The properties computed for the most stable isomers of Ag-N are in good agreement with the available experimental data. (c) 2006 American Institute of Physics.