AVS 47th International Symposium
    Surface Science Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM6
The Near Edge X-ray Absorption Fine Structure of n-octane Adsorbed on Cu(110): New Insights Into the Type of Chemical Interaction

Wednesday, October 4, 2000, 10:00 am, Room 208

Session: Chemical Interactions and Surface Reactivity
Presenter: K. Weiss, Uppsala University, Sweden
Authors: K. Weiss, Uppsala University, Sweden
L. Triguero, Uppsala University, Sweden
H. Öström, Uppsala University, Sweden
A. Nilsson, Uppsala University, Sweden
Correspondent: Click to Email
Using near edge X-ray absorption fine structure (NEXAFS) spectroscopy we have investigated the electronic structure of n-octane adsorbed on Cu(110). The molecule is found to be well oriented on the surface, which is seen from the high degree of NEXAFS dichroism. The NEXAFS spectra, which display the density of unoccupied molecular states, reveal large changes in the electronic structure of the adsorbed octane relative to the free molecule. We find that the molecular Rydberg states are strongly quenched upon adsorption and that there is a significant hybridization of molecular valence orbitals with the metal bands. In order to understand these adsorption induced electronic structure changes we have performed cluster model calculations in the framework of density functional theory. The calculations show nice agreement with the experimental results. In addition to a precise interpretation of the NEXAFS spectra, we present details on the geometric structure of the adsorbed octane molecule and the molecular orbital structure. The results are complemented by calculations of the X-ray emission spectra, which provide information on the occupied valence states. Our study gives new insights into the type of chemical interaction experienced by saturated hydrocarbons adsorbed on metal surfaces, which is of importance for the understanding of the C-H bond activation mechanism.