Author:

Keywords:

Science & Technology, Physical Sciences, Chemistry, Physical, Physics, Atomic, Molecular & Chemical, Chemistry, Physics, GENERALIZED-GRADIENT-APPROXIMATION, LONG-RANGE CORRECTION, CONSISTENT BASIS-SETS, CONVERGENT BASIS-SETS, METAL-CLUSTERS, DENSITY, NANOPARTICLES, CHEMISTRY, COMPUTATION, AG, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, 0306 Physical Chemistry (incl. Structural), 0307 Theoretical and Computational Chemistry, 3406 Physical chemistry, 3407 Theoretical and computational chemistry, 5102 Atomic, molecular and optical physics

Abstract:

Structural evolution and stability pattern of pure neutral gold clusters Aun in the small size range of n = 20-30 are examined using density functional theory (DFT) calculations. The equilibrium geometries are either confirmed or determined, and some new ground state structures are identified. The most stable configurations of Au21-Au23 sizes are formed by adding extra gold atoms to the highly stable pyramidal structure of Au20, while flat-cage shapes are the best candidates for the global minima of both Au24 and Au25. For larger sizes of n = 26-30, pyramidal motifs tend to dominate the lower-lying population rather than tubular conformations as previously reported. The energy gaps, excitation energies, and exciton binding energies are also computed to test out the performance of the computational methods employed. Accordingly, a density functional with long-range exchange effects is highly recommended to quantitatively investigate both the ground and excited states of pure gold clusters.