Thiolate Induced Reconstruction of Au(111) and Cu(111) Investigated by Density Functional Theory Calculations

The density functional theory is used to explore structural properties of alkyl-thiolate (RS) monolayers on Au(111) and Cu(111). RS adsorption drives pronounced, albeit qualitatively different, reconstruction of both surfaces. On Au(111), the stable structure comprises RS-Au-RS complexes with RS in atop positions, whereas a pseudo-(100) phase is favored for Cu(111) with a majority of the RS radicals in 4-fold hollow positions. The difference is attributed to a more covalent character of the RS-metal interaction for Au, together with a lower energetic penalty to form surface adatoms.