Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 9: Nanostructures at Surfaces I
O 9.5: Vortrag
Montag, 7. März 2016, 11:30–11:45, H6
Covalent or organometallic networks? A comparative study of a dibromo-diiodo-pyrene derivate on Ag(111) vs. Au (111) by XPS, NEXAFS, and STM — •Matthias Lischka1,2, Johanna Eichhorn1,2, Massimo Fritton1,2, Thomas Strunskus3, Vijay Vyas4, Wolfgang M. Heckl1,2,5, and Markus Lackinger1,2,5 — 1Department of Physics, TU München, James-Franck-Str. 1, 85748 Garching — 2Center for NanoScience, Schellingstr. 4, 80799 Munich — 3Institute for Materials Science - Multicomponent Materials, Christian-Albrechts- Universität zu Kiel, Kaiserstr. 2, 24143 Kiel — 4MPI für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart — 5Deutsches Museum, Museumsinsel 1, 80538 Munich
The thermally activated surface chemistry of a dibromo-diiodo-pyrene is comparatively studied on Ag(111) and Au (111) under ultrahigh vacuum conditions. X-ray photoelectron spectroscopy of C 1s, Br 3d, and I 3d was used to identify chemical changes that indicated the occurrence of two distinct phases for both surfaces. Upon progressive heating on Ag (111), an initially formed partly organometallic phase becomes fully organometallic. On Au (111) at room temperature, however the precursor is already deionated and partially forms covalent bonds. Further heating drives debromination and results in conversion to a fully covalent network. The structural characterization of each phase is carried out by a combination of high resolution scanning tunneling microscopy and C 1s near edge x-ray absorption fine structure. Special emphasis is put on buckling in the networks as a consequence of covalent bond formation due to steric hindrance.