Surface Structure and Chemistry of Alkanethiols on Au(100)-(1 × 1) Substrates

GRUMELLI, DORIS ELDA; LOBO MAZA, FLAVIA EMILIA; SALVAREZZA, ROBERTO; KERN, KLAUS; CARRO, PILAR

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015 vol. 120 p. 291 - 296

1932-7447

The surface structure of self-assembled monolayers ofhexanethiolate (HT) on the Au(100)-(1 × 1) surface has been studied bydensity functional theory (DFT) calculations and their results compared toscanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy(XPS) data. We have found two novel surface structure models consistingof adsorbed thiolates on the Au(100)-(1 × 1) surface that fairly account forexperimental STM and XPS observations. Surprisingly, these models exhibitbetter thermodynamic stability than those consisting of thiolate−Auad−thiolate moieties on a reconstructed Au(100)-(1 × 1) surface. Also theseproposed models are more stable than the thiolate−Auad−thiolate containingc(4 × 2) lattice on the reconstructed Au(111) suggesting a surface dependentchemistry for thiolates on Au. However, the possible existence of othermodels with similar or better stability than those proposed in this work andalso the possible coexistence of different surface structures and chemistry onthe substrate surface cannot be excluded.