A bonding study of cyclopentene (c-C5H8) adsorption on Ni(1 1 1) surface

Abstract

The adsorption of cyclopentene (c-C5H8) on Ni(1 1 1) was studied using DFT and semiempirical calculations. Preferred site and geometry calculations were carried out considering a Ni(1 1 1) surface and a unit cell of 64-atoms. The tetrahedral threefold hollow position was identified as the most favorable site, with a surface-molecule minimum distance of 1.83 Å. A bending structure is adopted when the molecule is adsorbed where the carbon atoms of the double bond are closer to the surface forming an angle of 160° among non-equivalents carbon atoms. The metal surface was represented by a two-dimensional slab with an overlayer of c-C5H8/Ni of 1/9 ratio. We also computed the density of states (DOS) and the crystal orbital overlap populations (COOP) corresponding to C{single bond}C, C{single bond}Ni, C{single bond}H, and Ni{single bond}Ni bonds. We found that both Ni{single bond}Ni bonds interacting with the ring, and the C{double bond, long}C bond are weakened after adsorption, this last bond is linked significantly to the surface. The hydrogen atoms belonging to the saturated carbon atoms also participate in the adsorbate-surface bonding. The main interactions include the 4s, 3pz and 5 dz2 bands of nickel and 2pz bands of the carbon atoms of the double bond. © 2008 Elsevier B.V. All rights reserved.