On the adsorption of hydrocarbons on deformable surfaces

The dimple appearing on a deformable metal surface upon physisorption of a foreign molecule is studied, and its effect on the adsorption energy is calculated. The surface energy contributes to the latter, the end effect being an increase of the adsorption energy due to the dimple formation. Specific attention is given to the case of hydrocarbons adsorbed on Au(lll), for which the dependence of the dimple shape and of the adsorption energy on the number of C atoms is studied, and the results are compared with the experimental data. The repulsion from the metal ion cores appears to be important for the longer molecules. The effect of molecular beading is also briefly considered. (C) 1999 Published by Elsevier Science B.V. All rights reserved.