274 research outputs found

    Barrier formation at organic interfaces in a Cu(100)-benzenethiolate-pentacene heterostructure

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    The energy level alignment at the metal-organic and organic-organic interfaces of the Cu(100)/benzenethiolate/pentacene heterostructure is studied by photoemission spectroscopy and discussed theoretically using a model that includes, in a consistent way, charge transfer, Pauli repulsion, intrinsic molecular dipoles, and interface screening as a function of coverage. Despite the different nature of the two interfaces, our model provides a unified explanation for the work-function changes at both junctions and enables us to determine the benzenethiolate orientation as a function of coverage

    Synthesis of Ternary Borocarbonitrides by High Temperature Pyrolysis of Ethane 1,2-Diamineborane

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    Ethane 1,2-diamineborane (EDAB) is an alkyl-containing amine-borane adduct with improved hydrogen desorption properties as compared to ammonia borane. In this work, it is reported the high temperature thermolytic decomposition of EDAB. Thermolysis of EDAB has been investigated by concomitant thermogravimetry-differential thermal analysis-mass spectrometry experiments. EDAB shows up to four H2 desorption events below 1000 ¬įC. Small fractions of CH4, C2H4 and CO/CO2 are also observed at moderate-high temperatures. The solid-state thermolysis product has been characterized by means of different structural and chemical methods, such as X-ray diffraction, Raman spectroscopy, Scanning electron microscopy, Elemental analysis, and X-ray photoelectron spectroscopy (XPS). The obtained results indicate the formation of a ternary borocarbonitride compound with a poorly-crystalline graphitic-like structure. By contrast, XPS measurements show that the surface is rich in carbon and nitrogen oxides, which is quite different to the bulk of the materialSome authors (Fabrice Leardini, Lorenzo Massimi, Maria Grazia Betti and Carlo Mariani) also thank Sapienza Universit√† di Roma for financial support under ‚ÄúProgetti di Ateneo‚ÄĚ, and the Italian Ministry of Education and Research (MIUR) for the PRIN grant ‚ÄúGRAF‚ÄĚ n. 20105ZZTS

    Atypical Bacterial Pathogens and Small-Vessel Leukocytoclastic Vasculitis of the Skin in Children: Systematic Literature Review.

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    Leukocytoclastic small-vessel vasculitis of the skin (with or without systemic involvement) is often preceded by infections such as common cold, tonsillopharyngitis, or otitis media. Our purpose was to document pediatric (‚ȧ18 years) cases preceded by a symptomatic disease caused by an atypical bacterial pathogen. We performed a literature search following the Preferred Reporting of Systematic Reviews and Meta-Analyses guidelines. We retained 19 reports including 22 cases (13 females and 9 males, 1.0 to 17, median 6.3 years of age) associated with a Mycoplasma pneumoniae infection. We did not find any case linked to Chlamydophila pneumoniae, Chlamydophila psittaci, Coxiella burnetii, Francisella tularensis, or Legionella pneumophila. Patients with a systemic vasculitis (N = 14) and with a skin-limited (N = 8) vasculitis did not significantly differ with respect to gender and age. The time to recovery was ‚ȧ12 weeks in all patients with this information. In conclusion, a cutaneous small-vessel vasculitis with or without systemic involvement may occur in childhood after an infection caused by the atypical bacterial pathogen Mycoplasma pneumoniae. The clinical picture and the course of cases preceded by recognized triggers and by this atypical pathogen are indistinguishable

    Molecular charge distribution and dispersion of electronic states in the contact layer between pentacene and Cu(119) and beyond

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    The interaction of pentacene molecules in contact with the Cu(119) stepped surface has been directly imaged by scanning tunneling microscopy and analyzed by angle resolved photoemission spectroscopy. Interacting molecules, which are in contact with copper, generate dispersive electronic states associated with a perturbed electron charge density distribution of the molecular orbitals. In contrast, the electron charge density of molecules of the pentacene on top of the first layer, which is not in direct contact with the Cu surface, shows an intramolecular structure very similar to that of the free molecule. Our results indicate that the delocalization of the molecular states in the pentacene/Cu system is confined to the very first molecular layer at the interface

    The local adsorption geometry of benzenethiolate on Cu(1 0 0)

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    The local adsorption geometry of benzenethiolate in the ordered c(2 √ó 6) phase on Cu(1 0 0) has been investigated by a combination of S K-edge near-edge X-ray absorption fine structure (NEXAFS), normal incidence X-ray standing waves (NIXSW) and S 1s scanned-energy mode photoelectron diffraction (PhD). NEXAFS and PhD show that the molecular plane is tilted from the surface normal by 20 ¬Ī 15¬į, while NIXSW clearly identifies the S head-group as occupying the four-fold coordinated hollow sites. PhD shows the S atoms lies 1.34 ¬Ī 0.04 √Ö above the outermost Cu atomic layer, leading to a Cu‚ÄďS bondlength of 2.25 ¬Ī 0.02 √Ö. The combination of the PhD and NIXSW results shows the Cu surface layer has an outward relaxation of 0.15 ¬Ī 0.06 √Ö. Possible origins for this large adsorbate-induced relaxation are discussed

    Measurement of CNGS muon neutrino speed with Borexino

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    We have measured the speed of muon neutrinos with the Borexino detector using short-bunch CNGS beams. The final result for the difference in time-of-flight between a =17 GeV muon neutrino and a particle moving at the speed of light in vacuum is {\delta}t = 0.8 \pm 0.7stat \pm 2.9sys ns, well consistent with zero.Comment: 6 pages, 5 figure

    Measurement of the cross section for isolated-photon plus jet production in pp collisions at ‚ąös=13 TeV using the ATLAS detector

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    The dynamics of isolated-photon production in association with a jet in proton‚Äďproton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 fb‚ąí1. Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti- algorithm with radius parameter and required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photon‚Äďjet invariant mass and the scattering angle in the photon‚Äďjet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements

    A search for resonances decaying into a Higgs boson and a new particle X in the XH ‚Üí qqbb final state with the ATLAS detector