Au as a Surrogate for F: The Case of UAu₆ vs UF₆

Here, anion photoelectron spectroscopy and first-principles quantum chemistry are used to demonstrate to what degree Au can act as a surrogate for F in UF₆ and its anion. Unlike UF₆, UAu₆ exhibits strong ligand-ligand, i.e., Au-Au, interactions, resulting in three low-lying isomers, two of which are three-dimensional while the third isomer has a ring-like quasi two-dimensional structure. Additionally, all the UAu₆ isomers have open-shell electrons, which in nearly all cases are localized on the central U atom. The adiabatic electron affinity and vertical detachment energy are measured to be 3.05 ± 0.05 and 3.28 ± 0.05 eV, respectively, and are in very good agreement with calculations.