AVS 50th International Symposium
    Surface Science Wednesday Sessions
       Session SS2-WeM

Paper SS2-WeM2
Molecule-Metal Surface Interactions Evidenced Quantum Mechanically via Tip-induced CS2 Interaction with Friedel Oscillations on Au{111}

Wednesday, November 5, 2003, 8:40 am, Room 327

Session: Surface and Interface Structure: Metals
Presenter: E.C.H. Sykes, The Pennsylvania State University
Authors: E.C.H. Sykes, The Pennsylvania State University
P. Han, The Pennsylvania State University
P.S. Weiss, The Pennsylvania State University
Correspondent: Click to Email
Sub-monolayer coverages of CS2 adsorbed on Au{111} at 4 K were studied using scanning tunneling microscopy. The molecule forms well ordered islands on the terraces and molecular chains at the bottoms of the steps. The adsorption of the CS2 molecule at specific surface sites is explained in terms of the substrate electron density. Strong tip/molecule interactions are shown to be prevalent in this system at negative tip biases and yield images showing reversed corrugation. At low positive tip bias, the tip again perturbs the molecules, but in this regime the tip/molecule interaction is comparable to the molecule/surface interaction and higher residence times at certain surface sites are observed. This effect is explained fully in terms of the CS2 molecule having increased interactions with the areas of high electron density on the peaks of standing waves arising from electrons close to the Fermi energy. The importance of this result is discussed in terms of the fundamental surface physics of adsorbate/metal bonding.