Benzene and carbon monoxide co-adsorption on Pt(1 1 1): a theoretical study

The co-adsorption of carbon monoxide and benzene on Pt(1 1 1) has been studied by theoretical tight-binding calculations. We used the ordered ð2 ffiffiffi 3 p 4Þ rect-2C6H6þ4CO superlattice. The computed energies for the adsorption sequences agrees with the experimental fact that CO displaces benzene. A comparison of the co-adsorption with CO and benzene 2D networks and both, CO and benzene 2D, adsorbed alone on Pt(1 1 1) is also given. An important H–H intermolecular interaction between benzenes is reinforced when CO is added to the surface. In addition, the Pt–C6H6 overlaps population decrease while a bonding interaction is developed between carbon from benzene and the C and O atoms from carbon monoxide. The density of states (DOS) and crystal orbital overlap population (COOP) curves clearly show this behavior.