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O: Fachverband Oberflächenphysik
O 59: Poster Session II (Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: arrays; Nanostructures at surfaces: Wires, tubes; Nanostructures at surfaces: Other; Plasmonics and nanooptics; Metal substrates: Epitaxy and growth; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsoprtion of organic / bio molecules; Metal substrates: Adsoprtion of inorganic molecules; Metal substrates: Adsoprtion of O and/or H; Metal substrates: Clean surfaces; Density functional theory and beyond for real materials)
O 59.86: Poster
Mittwoch, 24. März 2010, 17:45–20:30, Poster B1
L-tyrosine on Ag(111): universality of the amino acid 2D zwitterionic bonding scheme? — •Joachim Reichert1,3, Agustin Schiffrin2, Willi Auwärter1, Alexander Weber-Bargioni3, Matthias Marschall1, Martina Dell'Angela4, Dean Cvetko4, Gregor Bavdek4, Albano Cossaro4, Alberto Morgante4, and Johannes V. Barth1,3 — 1Physik Department E20, TU München, Germany — 2Max-Planck-Institut für Quantenoptik, Garching, Germany — 3Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada — 4C.N.R.-INFM, Laboratorio Nazionale TASK, Trieste, Italy
We present a combined study of the adsorption and ordering of the L-tyrosine amino acid on close-packed noble-metal surfaces in ultra-high vacuum by means of low-temperature STM, XPS and NEXAFS spectroscopy. Our high resolution topographical STM data reveal noncovalent molecular dimerization within the highly ordered one-dimensional nanostructures, which recalls the geometrical pattern already seen in the L-methionine/Ag(111) system and supports a universal bonding scheme for amino acids on the Ag(111) surface. XPS measurements reveal a zwitterionic adsorption, whereas NEXAFS experiments show a tilted adsorption configuration of the phenol moiety. This enables the interdigitation between aromatic side-chains of adjacent molecules via parallel-displaced Pi-Pi interactions which, along with the hydrogen-bonding capability of the hydroxyl functionality, could provide an explanation for the emergence of the self-assembled supramolecular nanoribbons.