Structure and Stability of the Water−Graphite Complexes

Abstract

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 accuracy of the DFT/CC method is first demonstrated by a comparison of the various interaction energies on the potential energy surface of water−benzene, water−naphthalene, and water−anthracene complexes with the data calculated at the coupled-cluster level at the basis set limit. 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 toward 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. The OH···π complexes (with one OH pointing toward the surface and the other OH being oriented along the surface) are ...