Sökning: "NEXAFS"

Visar resultat 6 - 10 av 38 avhandlingar innehållade ordet NEXAFS.

  1. 6. Probing unoccupied electronic states in aqueous solutions

    Författare :Lars-Åke Näslund; Anders Nilsson; Hendrik Bluhm; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; x-ray absorption; x-ray absorption spectroscopy; XAS; NEXAFS; water; liquid water; aqueous solution; hydrogen bond; hydrogen bond network; local geometry; Physics; Fysik;

    Sammanfattning : Water is one of the most common compounds on earth and is essential for all biological activities. Water has, however, been a mystery for many years due to the large number of unusual chemical and physical properties, e.g. decreased volume during melting and maximum density at 4 °C. LÄS MER

  2. 7. Effect of Substrate on Bottom-Up Fabrication and Electronic Properties of Graphene Nanoribbons

    Författare :Konstantin Simonov; Olof Karis; Nils Mårtensson; Alexei Preobrajenski; Alessandro Baraldi; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; graphene nanoribbons; bottom-up; substrate; metal contact; electronic structure; electron doping; PES; ARPES; NEXAFS; STM; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : Taking into account the technological demand for the controlled preparation of atomically precise graphene nanoribbons (GNRs) with well-defined properties, the present thesis is focused on the investigation of the role of the underlying metal substrate in the process of building GNRs using bottom-up strategy and on the changes in the electronic structure of GNRs induced by the GNR-metal interaction. The combination of surface sensitive synchrotron-radiation-based spectroscopic techniques and scanning tunneling microscopy with in situ sample preparation allowed to trace evolution of the structural and electronic properties of the investigated systems. LÄS MER

  3. 8. Controlling Electronic and Geometrical Structure of Honeycomb-Lattice Materials Supported on Metal Substrates : Graphene and Hexagonal Boron Nitride

    Författare :Nikolay Vinogradov; Nils Mårtensson; Karsten Horn; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; graphene; h-BN; electronic structure; adsorption; doping; nano-templates; PES; NEXAFS; LEEM; STM; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : The present thesis is focused on various methods of controlling electronic and geometrical structure of two-dimensional overlayers adsorbed on metal surfaces exemplified by graphene and hexagonal boron nitride (h-BN) grown on transition metal (TM) substrates. Combining synchrotron-radiation-based spectroscopic and various microscopic techniques with in situ sample preparation, we are able to trace the evolution of overlayer electronic and geometrical properties in overlayer/substrate systems, as well as changes of interfacial interaction in the latter. LÄS MER

  4. 9. Structure of Self-Assembled Monolayers on Gold Studied by NEXAFS and Photoelectron Spectroscopy

    Författare :Somsakul Watcharinyanon; Lars Johansson; Hans Siegbahn; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Self-assembled monolayer SAMs ; X-ray photoelectron spectroscopy XPS ; Near-edge X-ray absorption fine structure NEXAFS spectroscopy; Infrared reflection absorption spectroscopy IRRAS ; contact angle measurements; Kelvin probe measurements; oligo phenyleneethynylene OPE ; Porphyrin-functionalized OPE; Tetraphenylporphyrin; Ferrocene-terminated alkanethiol; thiol; silane; Au 111 ; Physics; Fysik; Physics; Fysik;

    Sammanfattning : Self-assembled monolayers (SAMs) provide well-defined and ordered films of molecules spontaneously chemisorbed on a surface. By designing molecules with desired functionalities, such molecular film can be interesting for a range of applications from molecular electronics to catalysis. LÄS MER

  5. 10. Photoelectron Spectroscopy on Atoms, Molecules and Clusters : The Geometric and Electronic Structure Studied by Synchrotron Radiation and Lasers

    Författare :Torbjörn Rander; Olle Björneholm; Gunnar Öhrwall; Maxim Tchaplyguine; Matthias Neeb; Uppsala universitet; []
    Nyckelord :Atomic and molecular physics; Free clusters; Electron spectroscopy; Doped clusters; Laser excitation; Alkali metals; Electronic structure; Geometric structure; X-ray photoelectron spectroscopy XPS ; Resonant Auger spectroscopy RAS ; Near-threshold x-ray absorption fine structure NEXAFS ; Ultraviolet photoelectron spectroscopy UPS ; Detuning; Ultra-fast dissociation UFD ; Sodium; Potassium; Oxygen; Bromomethane; Argon; Xenon; Krypton; Molecular field splitting; Core hole lifetime; Core excitation; Atom- och molekylfysik;

    Sammanfattning : Atoms, molecules and clusters all constitute building blocks of macroscopic matter. Therefore, understanding the electronic and geometrical properties of such systems is the key to understanding the properties of solid state objects. LÄS MER