Regensburg 2004 – wissenschaftliches Programm
O 38.1: Vortrag
Donnerstag, 11. März 2004, 15:45–16:00, H38
Electronic and geometrical structure of adsorbed small organic molecules: formate, 3-thiophene carboxylate and glycinate on Cu(110) surface — •Nicolae Atodiresei, Kurt Schroeder, and Stefan Blügel — Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich, Germany
The attachment of carboxylic acids and biological molecules to metal surfaces has very important applications like molecular recognition and biosensor development. One interest is focused in the property of chirality which can be induced by the absorption of organic molecules on surfaces.
We performed ’ab initio’ calculations based on density functional theory (DFT) using a projector augmented plane wave (PAW) method to obtain the equilibrium geometry of formate, 3-thiophene carboxylate and glycinate adsorbed on the Cu(110) surface. All molecules contain a carboxylate functional group (COO-) which binds to Cu atoms of the first layer via the oxygen atoms. In the case of formate and 3-thiophene carboxylate the functional group is sitting perpendicular to the Cu(110) surface. The relative energies of formate on Cu(110) with different coverages in (2x2) unit cell are discussed. For the saturation coverage of 3-thiophene carboxylate on Cu(110) ((2x1) unit cell) the thiophene ring is sitting perpendicular to the metal surface but rotated with 230 relative to the  direction. The glycinate molecules form a (3x2) unit cell with 2 flat-lying molecules. They bind to the Cu surface also via amino group ( H2N-). The heterochiral arrangement is found to be energetically more stable than the homochiral one because two hydrogen bonds per molecule can be formed.