Self-organization of cobalt-phthalocyanine on a vicinal gold surface revealed by scanning tunnelling microscopy

Adsorption of cobalt-phthalocyanine on Au(7 8 8) in the sub-monolayer coverage regime leads to a preferential occupation of step edges with the molecule plane tilted such as to bridge adjacent terraces. Molecules which adsorb on terraces leave the surface reconstruction of Au(7 8 8) unchanged and exhibit the propensity to occupy face-centered cubic stacking domains. Tunnelling spectroscopy in the centre of the molecule reveals cobalt d-orbital related features, while spectroscopy on the ligands shows the lowest unoccupied molecular orbital.