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 35.8: Poster

Tuesday, March 12, 2013, 18:15–21:45, Poster B1

Kinetic parameters of molecule dynamics and reactions determined with a scanning tunneling microscope at room temperature and above — •Michael Stark, Stefanie Ditze, Martin Drost, Florian Buchner, Elisabeth Zillner, Michael Röckert, Hans-Peter Steinrück, and Hubertus Marbach — LS. f. PC II and Interdisciplinary Center for Molecular Materials (ICMM), Universität Erlangen-Nürnberg, Egerlandstr. 3, D-91058

The knowledge of kinetic parameters is generally important for a detailed understanding of chemical and physical processes, like the self-assembly of molecular building blocks into supramolecular structures. In this study we investigate the kinetics of surface diffusion and the self-metalation reaction of 2H-tetraphenylporphyrin (2HTPP) on Cu(111). The determination of the corresponding parameters and activation energies is thereby based on experimental data acquired with a scanning tunneling microscope (STM) at room temperature and above in ultra-high vacuum. One the one hand the focus of this study is on the slow unidirectional diffusion of 2HTPP along the close packed atomic rows of Cu(111) and on the rotation of the latter molecules on the same substrate. We also investigated the surface-mediated self-metalation reaction of 2HTPP with Cu atoms from the Cu(111) substrate. By counting individual molecules in the corresponding ST micrographs we are able to determine the rate constants of this reaction at different sample temperatures and thus to determine the activation energy for the metalation reaction based on these values.

This work has been funded by the DFG through SFB 583