Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 35: Poster Session I (Metal, semiconductor and oxide substrates: structure and adsorbates; Graphene)
O 35.31: Poster
Tuesday, March 12, 2013, 18:15–21:45, Poster B1
Influence of Bromine groups on the molecular arrangement and adsorption of CuTPPBr8 on Au(111) — •Lars Smykalla1, Michael Hietschold1, and Heinrich Lang2 — 1Chemnitz University of Technology, Institute of Physics, D-09107 Chemnitz, Germany — 2Chemnitz University of Technology, Institute of Chemistry, D-09107 Chemnitz, Germany
The bromination of the molecule tetraphenyl-porphyrin leads to a very strong saddle-shape deformation of the macro-cycle and a change of the electronic states. We combine scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), photoemission spectroscopy (PES) and density functional theory (DFT) to thoroughly investigate the molecular arrangement and electronic structure of copper-2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin (CuTPPBr8) on the Au(111) surface. After slight annealing of the sample a well ordered adsorbate structure is observed. Thereby, the molecules are found to be rotated by 90∘ with respect to their neighbours in a checkerboard-like manner. Upon heating above 300∘C the molecular arrangement transforms into a stripe-like structure with two different kinds of molecular appearances, which is due to the debromination of the molecules as could be confirmed by PES. Furthermore, we present a comparison of our results obtained from STS, PES and DFT for the electronic structure of CuTPPBr8 adsorbed on Au(111) and discuss the interaction of the molecules with the substrate.