Investigation of the interaction of some astrobiological molecules with the surface of a graphite (0Â 0Â 0Â 1) substrate. Application to the CO, HCN, H2O and H2CO molecules

Detailed interaction potential energy calculations are performed to determine the potential energy surface experienced by the molecules CO, HCN, H2O and H2CO, when adsorbed on the basal plane (0 0 0 1) of graphite at low temperatures. The potential energy surface is used to find the equilibrium site and configuration of a molecule on the surface and its corresponding adsorption energy. The diffusion constant associated with molecular surface diffusion is calculated for each molecule.