Structural evolution and electronic properties of Au2Gen−/0 (n=1−8) clusters: Anion photoelectron spectroscopy and theoretical calculations

Abstract

Investigating the structures and properties of Au-Ge mixed clusters can give insight into the microscopic mechanisms in gold-catalyzed Ge films and can also provide valuable information for the production of germanium-based functional materials. In this work, size-selected anion photoelectron spectroscopy and theoretical calculations were used to explore the structural evolution and electronic properties of Au2Gen−/0 (n=1–8) clusters. It is found that the two Au atoms in Au2Gen−/0 (n=1–8) showed high coordination numbers and weak aurophilic interactions. The global minima of Au2Gen− anions and Au2Gen neutrals are in spin doublet and singlet states, respectively. Au2Gen− anions and Au2Gen neutrals showed similar structural features, except for Au2Ge4−/0 and Au2Ge5−/0. The C2v symmetric V-shaped structure is observed for Au2Ge1−/0, while Au2Ge2−/0 has a C2v symmetric dibridged structure. Au2Ge3−/0 can be viewed as the two Au atoms attached to different Ge–Ge bonds of Ge3 triangle. Au2Ge4− has two Au atoms edge-capping Ge4 tetrahedron, while Au2Ge4 neutral adopts a C2v symmetric double Au atoms face-capping Ge4 rhombus. Au2Ge5−8−/0 show triangular, tetragonal, and pentagonal prism-based geometries. Au2Ge6 adopts a C2v symmetric tetragonal prism structure and exhibits σ plus π double bonding characters.