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 et al., 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.