We have investigated various properties of divers gold nanostructures using ab initio density functional theory with spin-orbit coupling.
We have investigated the adsorption properties of chalcogen elements (oxygen and sulfur) and nitrogen on an anionic golden fullerene Au16- and its effects on the structural and electronic properties of the golden cage. In particular, we found that when a sulfur atom is encapsulated inside Au16-, its bonding character with Au atoms appears ionic due to electron transfer from sulfur to the gold nanocage. In contrast, the exohedrally adsorbed S atom tends to have strong orbital hybridization with the gold nanocage. For an oxygen adsorption case, electrons from the golden cage tend to be shared with the adsorbed O atom exhibiting strong orbital hybridization, regardless of its adsorption sites. To investigate the transition behaviors between the most stable exohedral and endohedral adsorption configurations, we calculate the activation and reaction energies in the transition. The oxygen atom experiences a lower energy barrier than the sulfur atom due to its smaller atomic radius. Finally, we explore the vibrational properties of S- or O-adsorbed Au16- 16 buckyballs by calculating their infrared spectra. When the N atom is adsorbed on the cage, electrons are transferred to nitrogen from Au 16. The nitrogen atom may move thermally from the exterior to the interior through a bridge site. In infrared spectra, exohedral doping causes greater intensities at higher frequencies than endohedral doping.
We have studied the dimerization of metal-encapsulated gold nanoclusters M@Au12 (M = W, Mo) with Ih or Oh symmetry, and their structural and electronic properties.To determine the most stable dimer structure in each case, various configurations are considered. We find that during dimerization, gold atoms near the interface tend to form inter-cluster triangular bonds, which stabilize two monomer clusters by about 3.3–3.5 eV. The dimerization along a specific axis selected as the z axis causes the symmetry reduction of each M@Au12 cluster resulting in the modification of electronic structures. It is found that all the stable dimers exhibit a much smaller HOMO–LUMO gap than those of their comprising monomers. Such a gap decrease is mainly attributed to the dz2 orbital splitting of the central atoms owing to dimerization. We also calculate the vibrational modes and the corresponding IRactive spectra, which are distinguishable for different dimer configurations. In addition, we find that the IR-active modes of the Oh-based dimer structures appear to be red-shifted in comparison to those of Ih-based ones. Thus, the IR spectra may be utilized experimentally to discriminate dimer configurations with different central metal atoms and/or dissimilar structural symmetries.
We have studied the 1D chain formation of metal-encapsulated gold nanoclusters M@Au12 (M = W, Mo) with Ih or Oh symmetry, and their structural and electronic properties.