0000000000012370
AUTHOR
Christian Stiehler
showing 5 related works from this author
Electron quantization in arbitrarily shaped gold islands on MgO thin films
2013
Low-temperature scanning tunneling microscopy has been employed to analyze the formation of quantum well states (QWS) in two-dimensional gold islands, containing between 50 and 200 atoms, on MgO thin films. The energy position and symmetry of the eigenstates are revealed from conductance spectroscopy and imaging. The majority of the QWS originates from overlapping Au 6p orbitals in the individual atoms and is unoccupied. Their characteristic is already reproduced with simple particle-in-a-box models that account for the symmetry of the islands (rectangular, triangular, or linear). However, better agreement is achieved when considering the true atomic structure of the aggregates via a densit…
Carbon Dioxide Activation and Reaction Induced by Electron Transfer at an Oxide-Metal Interface
2015
A model system has been created to shuttle electrons through a metal-insulator-metal (MIM) structure to induce the formation of a CO2 anion radical from adsorbed gas-phase carbon dioxide that subsequently reacts to form an oxalate species. The process is completely reversible, and thus allows the elementary steps involved to be studied at the atomic level. The oxalate species at the MIM interface have been identified locally by scanning tunneling microscopy, chemically by IR spectroscopy, and their formation verified by density functional calculations.
Gold/Isophorone Interaction Driven by Keto/Enol Tautomerization
2016
The binding behavior of isophorone (C9H14O) to Au adatoms and clusters deposited on MgO/Ag(001) thin films is investigated by scanning tunneling microscopy (STM) and density functional theory (DFT). The STM data reveal the formation of various metal/organic complexes, ranging from Au1/isophorone pairs to larger Au aggregates with molecules bound to their perimeter. DFT calculations find the energetically preferred keto-isophorone to be unreactive toward gold, while the enol-tautomer readily binds to Au monomers and clusters. The interaction is governed by electrostatic forces between the hydroxyl group of the enol and negative excess charges residing on the ad-gold. The activation barrier b…
Aktivierung und Elektronentransfer-induzierte Reaktion von Kohlendioxid an einer Oxid-Metall-Grenzfläche
2015
Es wurde ein Modellsystem realisiert, das mittels Elektronentransfer durch eine Metall-Isolator-Metall(MIM)-Struktur die Bildung eines CO2-Radikalanions von aus der Gasphase adsorbiertem Kohlendioxid induziert, welches anschliesend zu Oxalat weiterreagiert. Dieser reversible Prozess gestattet eine Studie der involvierten Elementarschritte auf atomarer Ebene. Die Oxalatspezies an der MIM-Grenzflache wurden mithilfe der Rastertunnelmikroskopie untersucht, chemisch mittels Infrarotspektroskopie identifiziert und ihre Bildung durch Dichtefunktionalrechnungen verifiziert.
Electron quantization in arbitrarily shaped Au islands on MgO thin films
2013
Low-temperature scanning tunneling microscopy has been employed to analyze the formation of quantum well states (QWS) in two-dimensional gold islands, containing between 50 and 200 atoms, on MgO thin films. The energy position and symmetry of the eigenstates are revealed from conductance spectroscopy and imaging. The majority of the QWS originates from overlapping Au 6p orbitals in the individual atoms and is unoccupied. Their characteristic is already reproduced with simple particle-in-a-box models that account for the symmetry of the islands (rectangular, triangular, or linear). However, better agreement is achieved when considering the true atomic structure of the aggregates via a densit…