Publications (2)0 Total impact
ABSTRACT: The Shockley-type surface state on noble metal (111) surfaces can be used as a sensitive probe for different surface modifications, adsorption processes, and interactions between adsorbate and substrate. On the model systems of Cu and Au(111) surfaces covered with noninteger monolayers of Ag we demonstrate that angle-resolved photoelectron spectroscopy is able to identify the growing positions of adsorbates by the investigation of the Shockley state. Vice versa, we discuss in a simple model to what extent the surface states themselves influence the adsorption process and determine the favored surface for physisorbed closed-shell systems.
Phys. Rev. B. 78(16).
ABSTRACT: We performed high-resolution photoemission experiments at different photon energies to investigate the valence band structure of 1 ML of 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTCDA) on Ag(1 1 1). Besides the known occupied molecular orbitals HOMO and HOMO − 1 we observe a new state close to the Fermi level, which results from the interaction between NTCDA and the substrate, partially filling the lowest unoccupied orbital of the free molecule (LUMO) in the monolayer system. By tuning the photon energy through the carbon K-edge, a resonance like change of the spectral intensity at the HOMO and HOMO − 1 energies is clearly revealed, which we use for an assignment of the individual spectral features to a predominant localization either at the naphthalene core or the anhydride group.