Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 30: Adsorption an Oberfl
ächen III
O 30.5: Vortrag
Montag, 7. März 2005, 11:45–12:00, TU EB301
Circular Dichroism in Core Level Photoemission from Tartaric Acid Adsorbed on Cu(110) — •JeongWon Kim, Jan Hugo Dil, Thorsten Kampen, and Karsten Horn — Fritz-Haber-Institut der MPG, Berlin
The adsorption of chiral molecules is an important step in the heterogeneous catalytic conversion of pro-chiral reagents into one of the possible optical isomers. Hence the occurrence of a chiral preference in adsorbed molecules has recently received considerable attention. While the arrangement of chiral molecules into a symmetry-breaking supra-molecular structure has been demonstrated in scanning tunnelling microscopy, a direct identification of the presence of chiral centers has so far not been achieved. Here we demonstrate circular dichroism in carbon 1s core level photoemission from the (R,R) and (S,S) enantiomers of tartaric acid [HOOC−(CHOH)2−COOH] adsorbed on Cu(110). The asymmetry in the core level spectra excited with right- and left circularly-polarized light is readily observed, and changes sign with the handedness of the radiation, or upon changing the nature of the enantiomers. We characterize the circular dichroism in order to differentiate between that induced by the handedness of the experimental geometry (CDAD) and that induced by the chiral center in the adsorbed molecule.