title: The reaction pathways for HSCH3 adsorption on Au(111): a density functional theory study.
abstract: Density functional theory was used to investigate the reaction pathways for HSCH(3) adsorption on Au(111) at low coverage. A molecular adsorbed state was found with the S atom bond on Top sites (E approximately -0.38 eV) and molecular adsorption is nonactivated. The H-SCH(3) dissociation process is energetically less favorable and becomes slightly exothermic only when surface relaxation is considered (DeltaE approximately -0.2 eV). All the reaction pathways present a sizable activation energy barrier, with the lowest being approximately 0.52 eV (0.41 eV taking into account slab relaxation). In the corresponding saddle point of the potential energy surface, the S atom of the methylthiolate molecule is placed on Top sites and the H near a Bridge site. The high barrier obtained explains the complete absence of reactive methanethiol dissociation found in recent experiments.
authors.affiliation: Centro Atómico Bariloche, and Instituto Balseiro, Av Bustillos 9500, 8400 S. C. de Bariloche, Argentina.
authors.forename: P G
authors.initials: PG
authors.lastname: Lustemberg
authors.forename: M L
authors.initials: ML
authors.lastname: Martiarena
authors.forename: A E
authors.initials: AE
authors.lastname: Martínez
authors.forename: H F
authors.initials: HF
authors.lastname: Busnengo