Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 36: Posters: Bio/organic Molecules on Surfaces, Graphene, Solid/liquid interfaces, Metal Substrates, Electronic Structure Theory

O 36.4: Poster

Dienstag, 1. April 2014, 18:30–22:00, P1

On the dynamics of molecular processes: STM investigations of porphyrins on Cu(111) — •Stefanie Ditze, Michael Stark, Martin Drost, Florian Buchner, Hans-Peter Steinrück, and Hubertus Marbach — Lehrstuhl für Physikalische Chemie II and Interdisciplinary Center for Molecular Materials (ICMM), Universität Erlangen-Nürnberg, Egerlandstr. 3, D-91058 Erlangen

For the controlled fabrication of molecular nanostructures it is important to understand dynamic processes such as surface diffusion, molecular rotation, conformational changes or chemical reactions on well-defined surfaces. Herein, we show that scanning tunneling microscopy (STM) can be a powerful tool to study the dynamics of porphyrins on Cu(111) under UHV conditions. The results of corresponding isothermal measurements at different temperatures are used for an Arrhenius type analysis to finally extract the energetics of the process. Following this route, the kinetic parameters for 2D surface diffusion and 2D molecular rotation of 2H-5,10,15,20-tetraphenylporphyrin (2HTPP) [1], the activation energy for the self-metalation reaction of 2HTPP with Cu substrate atoms [2] and finally even the energetics to conformational switch an individual 2H-5,10,15,20-tetrakis(3,5-di-tert-butyl)-phenylporphyrin can be determined.

This work has been funded by the DFG through SFB 583.

[1] F. Buchner et al., J. Phys. Chem. C 115 (2011) 24172-24177.

[2] S. Ditze et al., Angew. Chem., Int. Ed. 51 (2012) 10898-10901.