Ethene stabilised by halogens on Cu(111)

Temperature-programmed desorption studies have been carried out for a range of initial coverages of ethene adsorbed on equimolar chlorine and bromine covered Cu(111) surfaces (0–0.33 ML total halogen coverage) at 100 K. For the clean surface, ethene had an activation energy for desorption of 29±2 kJ...

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Bibliographic Details
Published in:Surface science 1997-04, Vol.377, p.719-723
Main Authors: Turton, S., Jones, Robert G.
Format: Article
Language:English
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Summary:Temperature-programmed desorption studies have been carried out for a range of initial coverages of ethene adsorbed on equimolar chlorine and bromine covered Cu(111) surfaces (0–0.33 ML total halogen coverage) at 100 K. For the clean surface, ethene had an activation energy for desorption of 29±2 kJ mol −1 at zero coverage, which decreased for increasing coverage, dropping to ∼27±2 kJ mol −1 for the highest coverage attainable at 103 K (using a fixed pre-exponential factor of 1 × 10 13 s −1). Chemisorbed chlorine and bromine stabilised the adsorbed ethene, the maximum effect occurring at 0.17 ML of Cl Br where the sticking probability increased to 1.4, and the saturation coverage to 2.5 times that of the clean surface at 103 K. At a combined Br Cl coverage of 0.25 ML, a particularly stable surface was formed for which the activation energy for ethene desorption was almost constant at 35±2 kJ mol −1. The ethene is thought to be coplanar with the halogens and bonded directly to the copper via its π orbital.
ISSN:0039-6028
1879-2758
DOI:10.1016/S0039-6028(96)01456-2