Prism rather than tetrahedron: low-energy structures for gaseous gold clusters Au10(O2)n+ by density functional calculations.

The purpose of this study is to reveal the adsorption mechanism of oxygen molecules on gold clusters. density functional theory is employed to investigate the low-energy structure of multiple O₂ adsorption on the Au₁₀⁺ cluster and findings are compared with IR spectra. The nature of bonding of the O₂ molecule and Au₁₀⁺ cluster has been characterised through several metrics like binding energy, dissociation energy, bond length, and vibrational frequencies. The result shows that the lowest-energy structures are prism-shaped rather than tetrahedron-shaped, where only one O₂ is chemically adsorbed while others are physically adsorbed. Chemically adsorbed η²-O₂ behaves like free O₂^–, forming a single electron π bond with Au₁₀⁺, while physically adsorbed η¹-O₂ does not result in an effective chemical bond and behaves like free O₂. This study provides insights into the mechanism of oxygen molecule adsorption on gold clusters and can contribute to further research on the catalytic mechanism of gold clusters. Highlights Lowest energy structures are prism-shaped rather than tetrahedron-shaped, which is supported by IR spectrum and chemical hardness. Chemically adsorbed O₂ is activated and displays structural and spectral features of free O₂^–, while physically adsorbed O₂ is close to free O₂ in vibrational frequency and bond length. Chemical adsorption is equivalent to a single electron π bond while physical adsorption forms no effective chemical bond due to the lack of electronic pairing between Au₁₀⁺ and O₂. [ABSTRACT FROM AUTHOR]