Catalytic activity of nanostructured Au: Scale effects versus bimetallic/bifunctional effects in low-temperature CO oxidation on nanoporous Au

• Lu-Cun Wang,
• Yi Zhong,
• Haijun Jin,
• Daniel Widmann,
• Jörg Weissmüller and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2013, 4, 111–128, doi:10.3762/bjnano.4.13

• were performed on a PANalytical MPD PRO instrument by using Cu Kα radiation (λ = 0.154 nm). The structural coherency was evaluated through the width of the Au(111) diffraction peaks by means of the Scherrer equation, DScherrer = (Κ·λ)/(β·cos θ), where K= 0.89 is the Scherrer constant, λ the wavelength

• . Quantitative evaluation of the TPD spectra yields nominal oxygen coverages of 1.5 and 0.04 monolayers (ML) for the fresh and the used NPG(Ag)-4 catalyst, respectively, assuming a specific surface area of 75 m2·g−1, and a Au surface atom density of 1.4 × 1015 atoms·cm−2 (surface density on Au(111)) [13]. For

• atomic surface oxygen species identified as the active species above. Different types have been proposed. Baker et al. proposed the existence of chemisorbed oxygen in threefold hollow sites, of a 2D surface oxide and of a (subsurface) oxide on Au(111) on the basis of vibrational spectroscopy data and

Channeling in helium ion microscopy: Mapping of crystal orientation

• Vasilisa Veligura,
• Gregor Hlawacek,
• Raoul van Gastel,
• Harold J. W. Zandvliet and
• Bene Poelsema

Beilstein J. Nanotechnol. 2012, 3, 501–506, doi:10.3762/bjnano.3.57

• intensity and data for the individual grains has been aligned by using the position of the strongest peak. We can understand the angular dependence of the SE yield if we view it as a direct result of the fcc structure of the crystallites in the Au{111} film. The insets in Figure 4a are models of the Au

• hydrogen-flame-annealed polycrystalline Au{111} film taken with a PE of 15 keV and an ion dose of 4.9 × 1014 cm−2. Relative sample rotation angles around the surface normal are 24°, 56° and 84°. The polar angle is fixed at 35°. FOV: 10 µm. HIM BSHe images of the hydrogen-flame-annealed polycrystalline Au

• {111} film. A PE of 20 keV and an ion dose of 1.11 × 1015 cm−2 has been used. The stage tilt was 0°. FOV: 15 µm. Comparison of contrast evolution in a standard HV and the used UHV HIM. The SE yield, which is proportional to the gray level in SE images, is plotted against the total dose for a HV system

Molecular-resolution imaging of pentacene on KCl(001)

• Julia L. Neff,
• Jan Götzen,
• Enhui Li,
• Michael Marz and
• Regina Hoffmann-Vogel

Beilstein J. Nanotechnol. 2012, 3, 186–191, doi:10.3762/bjnano.3.20

• organic electronic devices [13]. The adsorption of pentacene on various substrates has been investigated with diffraction methods and STM [14][15][16][17][18]. On single crystalline metal surfaces such as, e.g., Cu(110), Au(111) and Ag(111) [19][20][21][22][23][24], pentacene forms a wetting layer of flat

X-ray spectroscopy characterization of self-assembled monolayers of nitrile-substituted oligo(phenylene ethynylene)s with variable chain length

• Hicham Hamoudi,
• Ping Kao,
• Alexei Nefedov,
• David L. Allara and
• Michael Zharnikov

Beilstein J. Nanotechnol. 2012, 3, 12–24, doi:10.3762/bjnano.3.2

• Grenzflächen, Karlsruher Institut für Technologie, D-76344 Eggenstein-Leopoldshafen, Germany 10.3762/bjnano.3.2 Abstract Self-assembled monolayers (SAMs) of nitrile-substituted oligo(phenylene ethynylene) thiols (NC-OPEn) with a variable chain length n (n ranging from one to three structural units) on Au(111

• ) were studied by synchrotron-based high-resolution X-ray photoelectron spectroscopy and near-edge absorption fine-structure spectroscopy. The experimental data suggest that the NC-OPEn molecules form well-defined SAMs on Au(111), with all the molecules bound to the substrate through the gold–thiolate

• anchor and the nitrile tail groups located at the SAM–ambient interface. The packing density in these SAMs was found to be close to that of alkanethiolate monolayers on Au(111), independent of the chain length. Similar behavior was found for the molecular inclination, with an average tilt angle of ~33–36

When “small” terms matter: Coupled interference features in the transport properties of cross-conjugated molecules

• Gemma C. Solomon,
• Justin P. Bergfield,
• Charles A. Stafford and
• Mark A. Ratner

Beilstein J. Nanotechnol. 2011, 2, 862–871, doi:10.3762/bjnano.2.95

• functional theory employing the B3LYP functional and 6-311G** basis. The molecules were then chemisorbed (terminal hydrogens removed) to the FCC hollow binding site of a Au(111) surface with the Au–S bond length of 2.48 Å, taken from the literature [27]. Transport calculations by means of gDFTB construct the

STM study on the self-assembly of oligothiophene-based organic semiconductors

• Elena Mena-Osteritz,
• Marta Urdanpilleta,
• Erwaa El-Hosseiny,
• Berndt Koslowski,
• Paul Ziemann and
• Peter Bäuerle

Beilstein J. Nanotechnol. 2011, 2, 802–808, doi:10.3762/bjnano.2.88

• weak intermolecular van der Waals forces and molecule–substrate interactions, as well as intermolecular hydrogen bonding in the case of functionalized oligothiophenes [15][16][17]. The typical flat metallic substrates (HOPG, Au(111), Ag(111), etc.) employed in STM differ from the ITO electrodes used in

Effect of the environment on the electrical conductance of the single benzene-1,4-diamine molecule junction

• Shigeto Nakashima,
• Yuuta Takahashi and
• Manabu Kiguchi

Beilstein J. Nanotechnol. 2011, 2, 755–759, doi:10.3762/bjnano.2.83

• conduction. The substrate was Au (111), prepared by a flame-annealing and quenching method. For the measurements in liquid, a solution of BDA (10 mM) in water, tetraethylene glycol dimethyl ether (tetraglyme), or mesitylene was fed into the electrochemical cell. The Au tip was repeatedly moved in and out of

• contact with the Au(111) substrate at a rate of 100 nm/s. Conductance was measured during breaking of the Au contact, and was not dependent on the breaking speed below 100 nm/s. The bias voltage between the tip and substrate was 20 mV. The experiments were performed on three independent samples for each

Towards quantitative accuracy in first-principles transport calculations: The GW method applied to alkane/gold junctions

• Mikkel Strange and
• Kristian S. Thygesen

Beilstein J. Nanotechnol. 2011, 2, 746–754, doi:10.3762/bjnano.2.82

• -space projector-augmented wave method GPAW [53][54] with a grid spacing of 0.2 Å and the PBE functional for exchange and correlation (xc) [55]. The molecules were attached to Au(111) surfaces, modeled by an eight-layer-thick 4 × 4 slab, through small four-atom tips as shown in Figure 1a. The surface

• corresponding to double-zeta plus polarization (DZP) for the Au atoms and double-zeta (DZ) for the atoms of the molecules. We use rather diffuse basis functions with a confinement-energy shift of 0.01 eV. This ensures that the calculated work function of Au(111) and the Kohn–Sham energy levels of the molecular

Femtosecond time-resolved photodissociation dynamics of methyl halide molecules on ultrathin gold films

• Mihai E. Vaida,
• Robert Tchitnga and
• Thorsten M. Bernhardt

Beilstein J. Nanotechnol. 2011, 2, 618–627, doi:10.3762/bjnano.2.65

• methyl halide molecules on Au/Mo(100) Methyl iodide Figure 1a shows temperature-programmed desorption (TPD) spectra recorded after dosing different amounts of CD3I molecules at 90 K onto a 10 ML gold film grown on Mo(100). Similar to the TPD investigations of methyl iodide on Au(100) [11] and on Au(111

• evolution of the ethane signal in the temperature-programmed reaction of CD3I molecules on the 10 ML Au film on Mo(100). The ethane signal starts just below 300 K, extends up to 400 K and presents a maximum at 350 K. Based on similar results for Au(100) [11] and Au(111) [9], the ethane formation is thought

Terthiophene on Au(111): A scanning tunneling microscopy and spectroscopy study

• Berndt Koslowski,
• Anna Tschetschetkin,
• Norbert Maurer,
• Elena Mena-Osteritz,
• Peter Bäuerle and
• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 561–568, doi:10.3762/bjnano.2.60

• Abstract Terthiophene (3T) molecules adsorbed on herringbone (HB) reconstructed Au(111) surfaces in the low coverage regime were investigated by means of low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS) under ultra-high vacuum conditions. The 3T molecules adsorb preferentially in

• spectroscopic data reveals details of the contrast mechanism of 3T/Au(111) in STM. For that, the Shockley-like surface state of Au(111) plays an essential role and appears shifted outwards from the surface in the presence of the molecule. As a consequence, the molecule can be imaged even at a tunneling bias

• observed linear decrease of the differential tunneling barrier at positive bias when determined on top of a 3T molecule is compared to the bias independent barrier obtained on bare Au(111) surfaces. This striking difference of the barrier behavior with and without adsorbed molecules is interpreted as

Towards a scalable and accurate quantum approach for describing vibrations of molecule–metal interfaces

• David M. Benoit,
• Bruno Madebene,
• Inga Ulusoy,
• Luis Mancera,
• Yohann Scribano and
• Sergey Chulkov

Beilstein J. Nanotechnol. 2011, 2, 427–447, doi:10.3762/bjnano.2.48

• vibrational structure, STM–IETS can be used to determine the adsorption geometry of a 4-mercaptopyridine molecule on the Au(111) surface [4]. This study confirmed that a coordination of the sulfur atoms by two gold atoms (bridge site or defect site) is likely to be the preferred binding mode for the adsorbate

• method for the treatment of molecular systems with a large number of normal modes. Our implementation is very scalable and allows the investigation of larger systems such as an adsorbed 4-mercaptopyridine molecule on an Au(111) surface, using the partial Hessian method described in more details in the

• ) adsorbed on Au(111) (Figure 7) for different sizes of the partial Hessian matrix. The largest active system, mpy-ads-5, contains five gold atoms (the two gold atoms directly bonded to the sulfur atom, and the gold atoms which are bonded to both the first two gold atoms), thus yielding 48 normal modes. The

Influence of water on the properties of an Au/Mpy/Pd metal/molecule/metal junction

• Jan Kučera and
• Axel Groß

Beilstein J. Nanotechnol. 2011, 2, 384–393, doi:10.3762/bjnano.2.44

• units in possible nanoelectronic devices. We have investigated the interaction between water and a palladium monolayer of a Au(111)/4-mercaptopyridine/Pd junction by means of DFT calculations. A relatively strong bond between water and the palladium monolayer of the Au/Mpy/Pd complex is observed via a

• under potential control resulting in a metal layer on top of the SAM. The application of this technique led recently to the preparation of various metal/SAM/metal junctions on Au(111) electrodes, involving SAMs formed by 4-mercaptopyridine (Mpy) [1], 4-aminothiophenol (ATP) [2], thiazole [3], or 1,4

• interacting transition metal surfaces such as, e.g., Pd/Au(111) [19]. In this paper, we use periodic DFT calculations to focus on the interaction of water molecules with the palladium monolayer prepared on a 4-mercaptopyridine SAM on Au(111), forming a Au/Mpy/Pd/H2O complex. We determine the stability of an

Intermolecular vs molecule–substrate interactions: A combined STM and theoretical study of supramolecular phases on graphene/Ru(0001)

• Michael Roos,
• Benedikt Uhl,
• Daniela Künzel,
• Harry E. Hoster,
• Axel Groß and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2011, 2, 365–373, doi:10.3762/bjnano.2.42

• phases described for other substrates such as HOPG [27][28][29] and various metal substrates such as Au(111) [30][31][32][33][34], Ag(110) [35] or Cu(110) [36]. In contrast to the weakly interacting BTP molecules, the PTCDA adlayer covers the entire surface, i.e., the PTCDA molecules follow the up and

Recrystallization of tubules from natural lotus (Nelumbo nucifera) wax on a Au(111) surface

• Sujit Kumar Dora and
• Klaus Wandelt

Beilstein J. Nanotechnol. 2011, 2, 261–267, doi:10.3762/bjnano.2.30

• Sujit Kumar Dora Klaus Wandelt Institute of Physical and Theoretical Chemistry, Bonn University, Wegelerstrasse 12, 53115 Bonn, Germany 10.3762/bjnano.2.30 Abstract We present here the first results on the self-assembly of tubules of natural wax from lotus leaves on a single crystal Au(111

• ) surface. A comparison of the tubule growth on Au(111) to that on HOPG is discussed. Although the tubule formation on both Au(111) and HOPG takes place on an intermediate wax film which should mask the substrate properties, the tubule orientations differ. In contrast to a vertical tubule orientation on

• HOPG, the tubules lie flat on Au(111). Taking into account the physical properties of HOPG and Au(111), we put forward a hypothesis which can explain the different tubule orientations on both substrates. Keywords: AFM; Au(111); lotus wax; Introduction Natural nonacosan-10-ol waxes derived from plant