Adsorption of Ethylene and Acetylene Molecules on Ag (110) Surface

The adsorption of ethylene and acetylene molecules on Ag (110) surface has been investigated by using density-functional theory with and without consideration of dispersion (van der Waals interactions) between molecules and the surface. We find that both molecules prefer to adsorb on atop site of the step edge in comparison to the short bridge, long bridge and hollow sites. Our results indicate the weak interaction between adsorbates and substrate and the molecular geometry are almost unaffected by adsorption. The new results including dispersion in our calculations for the most stable site (atop) of ethylene and acetylene molecules on Ag (110) surface; show a good agreement with experimental adsorption energy especially for acetylene.