Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 45: Organic-Inorganic Hybrid Systems and Organic Films
O 45.18: Poster
Dienstag, 21. März 2017, 18:30–20:30, P1A
Surface crystallography of large organic molecules on metal and insulator surfaces by LEED-IV using Fourier coefficients — •Ina Krieger1,3, Georg Held2, Christian Kumpf3, and Moritz Sokolowski1 — 1Institut für Physikalische und Theoretische Chemie, Universität Bonn, 53115 Bonn, Germany — 2Department of Chemistry, University of Reading and Diamond Light Source, UK — 3Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52428 Jülich, Germany
We will report on LEED-IV analysis of the large organic molecules PTCDA and NTCDA on the metal and insulator surfaces Ag(100), Ag(111), and KCl(100). Using data from different angles of electron incidence and optimizing the LEED-IV program code we were able to extend the experimental data set and shorten the calculation times required for the complex and large unit cells. Furthermore, the distortion of the PTCDA molecule and the buckling of the Ag surface were described by Fourier coefficients taking into account the symmetry of the system [1]. The idea of this procedure is to suppress unphysical vertical displacements of atoms on a short-wave-length scale by restriction to lower order coefficients.
By this, we obtain good Pendry R-factors, for PTCDA/Ag100 of about 0.23. We were able to derive the vertical distortions of the oxygen atoms in the functional group and the buckling of the Ag surface in rather good agreement with earlier results from DFT and NIXSW studies.
[1] W. Moritz et al, Phys. Rev. Lett. 104, 136102 (2010).