title: X-ray diffraction and computation yield the structure of alkanethiols on gold(111).
abstract: The structure of self-assembled monolayers (SAMs) of long-chain alkyl sulfides on gold(111) has been resolved by density functional theory-based molecular dynamics simulations and grazing incidence x-ray diffraction for hexanethiol and methylthiol. The analysis of molecular dynamics trajectories and the relative energies of possible SAM structures suggest a competition between SAM ordering, driven by the lateral van der Waals interaction between alkyl chains, and disordering of interfacial Au atoms, driven by the sulfur-gold interaction. We found that the sulfur atoms of the molecules bind at two distinct surface sites, and that the first gold surface layer contains gold atom vacancies (which are partially redistributed over different sites) as well as gold adatoms that are laterally bound to two sulfur atoms.
authors.affiliation: Istituto Nazionale per la Fisica della Materia-Consiglio Nazionale delle Ricerche (INFM-CNR) Laboratorio TASC, I-34012 Trieste, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Cossaro
authors.forename: R
authors.initials: R
authors.lastname: Mazzarello
authors.forename: R
authors.initials: R
authors.lastname: Rousseau
authors.forename: L
authors.initials: L
authors.lastname: Casalis
authors.forename: A
authors.initials: A
authors.lastname: Verdini
authors.forename: A
authors.initials: A
authors.lastname: Kohlmeyer
authors.forename: L
authors.initials: L
authors.lastname: Floreano
authors.forename: S
authors.initials: S
authors.lastname: Scandolo
authors.forename: A
authors.initials: A
authors.lastname: Morgante
authors.forename: M L
authors.initials: ML
authors.lastname: Klein
authors.forename: G
authors.initials: G
authors.lastname: Scoles