Structural Evolution and Electronic Properties of Au2Gen-/0 (n=1-8) Clusters: Anion Photoelectron Spectroscopy and Theoretical Calculations

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 C-2v symmetric V-shaped structure is observed for Au2Ge1-/0, while Au2Ge2-/0 has a C-2v symmetric dibridged structure. Au2Ge3-/0 can be viewed as the two Au atoms attached to different Ge-Ge bonds of Ge-3 triangle. Au2Ge4- has two Au atoms edge-capping Ge-4 tetrahedron, while Au2Ge4 neutral adopts a C-2v symmetric double Au atoms face-capping Ge-4 rhombus. Au2Ge5-8-/0 show triangular, tetragonal, and pentagonal prism-based geometries. Au2Ge6 adopts a C-2v symmetric tetragonal prism structure and exhibits sigma plus pi double bonding characters.