ADSORPTION BEHAVIOR OF CO AND C2H2 ON THE GRAPHITE BASAL SURFACE: A QUANTUM CHEMISTRY STUDY

The adsorption of CO and C2H2 molecules on the perfect basal surface of graphite is investigated by adopting cluster models in conjunction with quantum chemical calculations. The noncovalent interaction potential energy curves for three different orientations of CO and C2H2 molecules with respect to the inert basal plane of graphite are calculated via semi-empirical and Moller-Plesset ab initio methods. Then, we have considered the effects of interaction energies on the Ca parts per thousand O and Ca parts per thousand C bond lengths by performing the partial geometry optimization procedure on the CO-graphite and C2H2-graphite systems in various intermolecular distances. The computational analysis of all physical noncovalent potential energy curves reveals that the relative configurations in which CO and C2H2 molecules approach the graphite sheet from out of the plane have stronger interaction energy and so is more favorable from the energetic viewpoint. This means that the graphite layer prefers to increase its thickness via the chemical vapor deposition of CO and C2H2 on the graphite.