Adsorption properties of chalcogen atoms on a golden buckyball Au16(-) from first principles

Using first-principles density functional theory, we investigate the adsorption properties of chalcogen elements (oxygen and sulfur) on an anionic golden nanocage Au(16)(-) and its effects on the structural and electronic properties of the golden cage. In particular, we find that when a sulfur atom is encapsulated inside Au(16)(-), 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 golden 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 Au(16)(-) buckyballs by calculating their infrared spectra.