title: Trapping of Charged Gold Adatoms by Dimethyl Sulfoxide on a Gold Surface.
abstract: We report the formation of dimethyl sulfoxide (DMSO) molecular complexes on Au(111) enabled by native gold adatoms unusually linking the molecules via a bonding of ionic nature, yielding a mutual stabilization between molecules and adatom(s). DMSO is a widely used polar, aprotic solvent whose interaction with metal surfaces is not fully understood. By combining X-ray photoelectron spectroscopy, low temperature scanning tunneling microscopy, and density functional theory (DFT) calculations, we show that DMSO molecules form complexes made by up to four molecules arranged with adjacent oxygen terminations. DFT calculations reveal that most of the observed structures are accurately reproduced if, and only if, the negatively charged oxygen terminations are linked by one or two positively charged Au adatoms. A similar behavior was previously observed only in nonstoichiometric organic salt layers, fabricated using linkage alkali atoms and strongly electronegative molecules. These findings suggest a motif for anchoring organic adlayers of polar molecules on metal substrates and also provide nanoscale insight into the interaction of DMSO with gold.
authors.affiliation: Physics Department, University of Trieste , Via A. Valerio 2, 34127 Trieste, Italy.|TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy.
authors.forename: Zhijing
authors.initials: Z
authors.lastname: Feng
authors.affiliation: Engineering and Architecture Department, University of Trieste , Via A. Valerio 6/1, 34147 Trieste, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Velari
authors.affiliation: TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy.
authors.forename: Albano
authors.initials: A
authors.lastname: Cossaro
authors.affiliation: TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Castellarin-Cudia
authors.affiliation: TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Verdini
authors.affiliation: Physics Department, University of Trieste , Via A. Valerio 2, 34127 Trieste, Italy.|TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy.
authors.forename: Erik
authors.initials: E
authors.lastname: Vesselli
authors.affiliation: Physics Department, University of Trieste , Via A. Valerio 2, 34127 Trieste, Italy.|TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Dri
authors.affiliation: Physics Department, University of Trieste , Via A. Valerio 2, 34127 Trieste, Italy.|CNR-IOM DEMOCRITOS , Area Science Park, S.S. 14 km 163.5, 34149 Trieste, Italy.|Consorzio Interuniversitario Nazionale per la Scienza e la Tecnologia dei Materiali (INSTM), Unità di ricerca di Trieste , Piazzale Europa 1, 34128 Trieste, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Peressi
authors.affiliation: Engineering and Architecture Department, University of Trieste , Via A. Valerio 6/1, 34147 Trieste, Italy.|Department of Physics, King's College London , Strand, London WC2R 2LS, United Kingdom.
authors.forename: Alessandro
authors.initials: A
authors.lastname: De Vita
authors.affiliation: Physics Department, University of Trieste , Via A. Valerio 2, 34127 Trieste, Italy.|TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Comelli
keywords: DMSO; adatom; density functional theory; dimethyl sulfoxide; gold; photoemission spectroscopy; scanning tunneling microscopy