The interaction of the water molecule with benzene, polycyclic aromatic hydrocarbons, graphene and graphite is investigated at the density-functional/coupled-cluster (DFT/CC) level of theory. The potential energy surface of water-graphene and water-graphite is relatively flat with diffusion barriers of about 1 kJ/mol.
The structure with both hydrogen atoms of water pointing towards the graphene plane (denoted as a circumflex structure) above the center of the six-member ring is the global minimum characterized with an electronic interaction energy of -13 and -15 kJ/mol for graphene and graphite, respectively.