Web Release Date: July 26,
Rich Coordination Chemistry of Au Adatoms in Gold Sulfide Monolayer on Au(111)
and#
Division of Engineering and Applied Sciences, Department of Chemistry and Chemical Biology, Center for Nanoscale Science, Department of Physics, Harvard University, Cambridge, Massachusetts 02138, and Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
Received: July 2, 2006
Abstract:
The rich chemistry of Au nanoparticles and ions has attracted tremendous interest, in part because the surfaces of bulk Au have traditionally been considered to be chemically inert. On the other hand, large-scale mass transport and the formation of vacancy islands have been observed on the Au(111) surface following the deposition of adsorbates, such as sulfur and thiols, that can interact strongly with the Au surface. In this work, we revisit the structure and chemistry of an ordered incommensurate AuS adlayer that forms on Au(111) following the deposition of sulfur and annealing to 450 K. A structural model of this AuS surface phase has not yet been determined experimentally due to the complexity of the system. Here, we use state-of-the-art density functional theory to develop an atomic-scale model that is consistent with the previously reported Au-S stoichiometry. In particular, we introduce theoretical techniques to take into account the charge transfer in an incommensurate system. Our model reproduces convincingly STM images and is remarkably robust. Bonding analysis based on Wannier functions shows that the model exhibits rich coordination chemistry corresponding to different Au oxidation states. The extraordinary stability and rich chemistry of this structure have implications for related S-Au interfaces and previously reported surface features of this system.
Download the full text: PDF | HTML
