Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 52: Metal substrates: Adsorption of organic / bio molecules VII
O 52.14: Vortrag
Donnerstag, 26. März 2009, 18:15–18:30, SCH A118
The Adsorption of Porphine on Copper (110) — •Matthew Stephen Dyer, Abel Robin, Sam Haq, Rasmita Raval, and Mats Persson — University of Liverpool, Liverpool, U. K.
Porphyrin molecules and related phthalocyanines have come under a lot of interest in recent years as potential components for molecular-scale devices with various applications. By studying the simplest porphyrin, porphine (H2-P), and its interaction with a clean copper surface we obtain physical insight relevant for larger, more complicated systems.
We present the results of scanning tunnelling microscopy (STM) and reflection absorption infrared spectroscopy (RAIRS) experiments, along with density functional theory (DFT) calculations, which show that H2-P is chemisorbed on Cu(110) with the centre above the short-bridge site. Considerable charge transfer occurs upon adsorption from the metal into the unoccupied orbitals of the molecule.
An unexpected and very interesting result is that copper adatoms are observed to reside in the vicinity of H2-P molecules in STM images. DFT calculations show that there is an energetic preference of about 25 meV for copper adatoms to reside in certain sites on the surface close to H2-P molecules. There is no chemical bond formed between the molecule and the adatom, rather the attraction is probably due to a substrate-mediated interaction.