IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Thursday Sessions
       Session SS3-ThP

Paper SS3-ThP9
Acetylene on Cu(110): Trimerization and Chemical Bonding

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Surface Reactions Poster Session
Presenter: H. Öström, Uppsala University, Sweden
Authors: H. Öström, Uppsala University, Sweden
L. Triguero, Uppsala University, Sweden
K. Weiss, Uppsala University, Sweden
D. Nordlund, Uppsala University, Sweden
H. Ogasawara, Uppsala University, Sweden
L.G.M. Pettersson, Stockholm University, Sweden
A. Nilsson, Uppsala University, Sweden and Stanford University
Correspondent: Click to Email
We have studied the chemical bonding of acetylene on Cu(110) and the well known trimerisation reaction to benzene by high resolution X-ray photoelectron spectroscopy (XPS), near edge X-ray absorption fine structure (NEXAFS) spectroscopy and X-ray emission spectroscopy (XES). At liquid nitrogen temperature the XP spectra show two different C 1s peaks which correspond to two nonequivalent acetylene species adsorbed in different sites. By heating the sample, one species transforms into the other. This species disappears above room temperature due to the trimerisation of acetylene to benzene. We monitored the reaction with time resolved XPS, finding that benzene leaves the surface as soon as it is formed, in agreement with previous results. The adsorption geometry of the different adsorbate species have been determined by polarization dependent NEXAFS spectra, which shows that both species lie down on the surface, with different molecular alignment. XES shows that both species are chemisorbed on the surface with their electronic structure significantly distorted from the gas phase. The experimental results are completed by ab-initio cluster model calculations performed in the framework of density functional theory (DFT).