Ordered (3 × 4) high-density phase of methylthiolate on Au(111)

Valentina De Renzi, Rosa Di Felice, Diego Marchetto, Roberto Biagi, Umberto Del Pennino, Annabella Selloni

Research output: Contribution to journalLetterpeer-review

58 Scopus citations


The formation of ordered phases of dimethyl-disulfide on the Au(111) surface has been investigated by means of low-energy electron diffraction (LEED), X-ray photoemission spectroscopy (XPS), and state-of-the-art density-functional theory (DFT) periodic supercell calculations. The LEED diffraction pattern, obtained after a production method that includes two-step dosing and prolonged postdeposition annealing, unambiguously corresponds to a novel phase that consists of (3 × 4) domains coexisting with the as-deposited (√3 × √3)R30° structure. XPS measurements indicate that the coverage of the new (3 × 4) superstructure is the same as that of the (√3 × √3)R30° phase. In both phases, the binding energy of the S 2p3/2 core-level peak is found to be 162.2 eV, corresponding to the formation of a thiolate layer. The DFT calculations allow us to identify a viable metastable (3 × 4) structure where the S headgroups of the CH3S radicals select distinct adsorption sites; three quarters of them adsorb at bridge sites and one quarter at top sites. The relative energetics of the (3 × 4) and (√3 × √3)R30° configurations suggest that the two structures may coexist on the surface, in agreement with experimental data.

Original languageEnglish (US)
Pages (from-to)16-20
Number of pages5
JournalJournal of Physical Chemistry B
Issue number1
StatePublished - Jan 8 2004

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry


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