Structural evolution of Au nanoclusters: From planar to cage to tubular motifs

Abstract

The evolution of structural motifs of gold cluster anions, Au n − , in the size range n = 11-24 has been determined through a comparison of electron diffraction data with density functional calculations. The results provide clear evidence for a transformation from planar to three-dimensional structures in the range n = 12-14, the development of cage structures for n = 16 and 17, the appearance of a tetrahedral structure at n = 20, and the emergence of a highly symmetric tubular structure for n = 24.

Determining the size-dependent structure of ligand-free gold-cluster ions

“…The structure of Au − 20 has been inferred to be a slightly distorted tetrahedron (D 2d ) by photoelectron spectroscopy (PES) . This was later confirmed in a TIED study (Xing et al 2006). Our results are fully consistent with these findings: the slightly (Jahn-Teller) distorted tetrahedron, a segment of the gold face-centred cubic (fcc) structure, is the ground-state structure according to TPSS/7s5p3d1f.…”

“…To our knowledge, neither the C 2 nor the planar structure has been considered for Au − 14 before. In former TIED (Xing et al 2006) and PES (Häkkinen et al 2003;Bulusu et al 2006) studies, a C 2v structure was assigned, which is a saddle-point rather than a minimum-energy structure using TPSS/7s5p3d1f. For Au − 15 , a flat-layered structure (C 2v ) closely related to the Au − 14 structure is the best-fitting isomer, in agreement with previous TIED measurements.…”

“…At the same time, several other groups also worked on structural determination of gold clusters (in various charge states) using complementary/identical experimental methods. In particular, structures were assigned via comparison of quantum chemical calculations to: (i) highresolution photoelectron spectra of cluster anions (Häkkinen et al 2003;Li et al 2003;Bulusu et al 2006;Yoon et al 2007), (ii) infrared multi-photon-dissociation spectra of neutral gold clusters complexed to one or two krypton atoms (Gruene et al 2008), and (iii) trapped ion electron diffraction (TIED) measurements on mass-selected gold-cluster anions (Xing et al 2006). We compare our results to these experiments as necessary.…”

Fluxionality of gold nanoparticles investigated by Born-Oppenheimer molecular dynamics

“…Some technical details of the computational times involved in the dynamic simulation have been added in the section dedicated to the "computational methods" section, in order to give an idea of their feasibility. gold for cage-like structures has been noted by several researchers [41,[70][71][72].…”

“…Born Oppenheimer molecular dynamics (BOMD) is a very refined tool for the theoretical investigation of dynamical phenomena in metal cluster [25,[39][40][41][42]. In the present investigation we have studied the dynamics of interconversion, the structural and electronic properties of gold nanoparticles in the size range of 0.5-1.0 nm (Au 12, Au 13, Au 14, Au 15, Au 20, Au 34, Au 55) using BOMD.…”