C2H4 adsorption on Cu(210), revisited: bonding nature and coverage effects

Abstract

With the aid of density functional theory (DFT)-based calculations, we investigate the adsorption of C₂H₄ on Cu(210). We found two C₂H₄ adsorption sites, viz., the top of the step-edge atom (S) and the long bridge between two step-edge atoms (SS) of Cu(210). The step-edge atoms on Cu(210) block the otherwise active terrace sites found on copper surfaces with longer step sizes. This results in the preference for π-bonded over di-σ-bonded C₂H₄. We also found two stable C₂H₄ adsorption orientations on the S- and SS-sites, viz., with the C₂H₄ CC bond parallel (fit) and perpendicular (cross) to [001]. Furthermore, we found that the three peaks observed in previous temperature programmed desorption (TPD) experiment [Surf. Sci., 2011, 605, 934–940] could be attributed to C₂H₄ in the S-fit or S-cross, S-fit and S-cross-fit (S-cross and S-fit configurations that both exist in the same unit cell) configurations on Cu(210).