Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 14: Metal substrates: Adsorption of organic / bio molecules II

O 14.8: Talk

Monday, March 22, 2010, 16:45–17:00, H36

Self-assembled monolayers of molecules with dithiol anchor groups: a DFT study — •Katrin Tonigold and Axel Groß — Institute for Theoretical Chemistry, Ulm University, D-89069 Ulm, Germany

Traditionally, either aliphatic or aromatic thiols are used to prepare self-assembled monolayers on gold surfaces. If both types of thiol groups are combined in the anchor group of a molecule, the size of the anchor group as well as its electronic structure are changed. Competing reactions between the two different S-atoms and the Au-surface might take place possibly leading to different surface structures.

A molecule that contains such a dithiol anchor group is 2-Mercaptomethylbenzenethiol (MMBT). In cooperation with experimentalists from the Institute of Functional Interfaces of the Karlsruhe Institute of Technology we have studied the adsorption and structure formation of MMBT on Au(111) using DFT-GGA-calculations with semi-empirical corrections for dispersion effects. IR spectra and STM images have been simulated to allow a comparison with experimental results [1]. Furthermore, the formation of surface defects upon adsorption has been addressed.

[1] X. Stammer, K. Tonigold, M. Kind, A. Groß, Ch. Wöll et al., in preparation.