Regensburg 2002 – scientific programme

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O: Oberflächenphysik

O 4: Oberfl
ächenreaktionen (I)

O 4.6: Talk

Monday, March 11, 2002, 12:30–12:45, H43

Intermolecular chiral recognition: Cysteine on Au(110) — •Angelika Kühnle, Trolle Linderoth, Bjørk Hammer, and Flemming Besenbacher — Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus, Denmark

We have investigated the adsorption of the chiral amino acid cysteine on the missing-row reconstructed Au(110)-(1x2) surface by UHV-STM. At temperatures above 340 K, L cysteine forms isolated molecular pairs that break the mirror symmetry of the gold surface. Molecules of the opposite chirality form identical, but mirror-reflected, pairs, demonstrating how STM can reveal the molecular chirality at the level of the individual pairs. Furthermore, deposition of the racemic DL mixture exclusively leads to the previously seen homochiral pairs and no structures suggesting DL pairing are found, demonstrating that heterochiral DL interaction is avoided. Ab-initio density-functional theory (DFT) calculations have been carried out to unravel the atomic-scale origin of this chiral discrimination.