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O: Oberflächenphysik
O 47: Organic films IV
O 47.4: Vortrag
Freitag, 31. März 2006, 12:00–12:15, PHY C213
Adsorption behavior of the amino acid DOPA on single crystalline Au(110) surfaces — •Mirko Weinhold1, Ruslan Temirov2, Serguei Soubatch2, and Stefan Tautz2 — 1Universität Bremen — 2International University Bremen
In investigations of proteins which are responsible for strong mussel adhesion, an unusually frequent appearance of the otherwise rare amino acid 3-(3,4-Dihydroxyphenyl)-L-alanine (DOPA) has been observed. This amino acid is thought to play a major role in the mechanism of mussel adhesion. Here we report an investigation of the molecule-substrate interaction between DOPA and the Au(110) surface. Several spectroscopic techniques (HREELS, LEED, XPS, IR) have been applied. Although DOPA decomposes close to the sublimation point, vapour deposition of the intact molecule without additional contamination turns out to be possible. DOPA molecules form a commensurate superlattice on Au(110). The chirality of the molecule leads to a one-domain chiral surface. Vibrational spectroscopy in conjunction with density functional calculations proves that DOPA adsorbs on Au(110) in its zwitter-ionic state. Annealing a DOPA/Au(110) monolayer to 550 K leads to partial desorption of the monolayer as well as catalyzed oxidation of DOPA to DOPAquinone.