A new method for the calculation of the interaction between atoms and small molecules and graphene-based surfaces

Abstract

The interaction between molecules and graphene is a topic of great interest. For instance, porous graphene films that could be used as nanofilters of atmospheric molecules have been recently synthesized[1]. To carry out computational simulations of this type of processes, it is desirable to employ realistic interaction potentials given by simple functional forms. We report global interaction potentials for the physisorption of rare gas (Rg= He, Ne, Ar and Kr) atoms on graphene and graphite[2]. An atom-bond pair-wise additive representation is used, where the interaction pairs are constituted by the Rg atom and the C-C bonds of the graphene sheet(s). The parameters of the analytical function describing the atom-bond potential are derived from the polarizabilities of the interaction partners and, in a second step, they are fine-tuned from accurate ab initio calculations of the prototypical Rg-coronene system. The Rg-graphene/graphite interaction potential obtained in this way is further expanded in a Fourier series and the corresponding coefficients are fitted to simple functional forms. Well depths and equilibrium distances compare quite well with several recent calculations. Moreover, the long range dispersion coefficient C3 and the calculated binding energies of Rg-graphite are in a rather good agreement with experimental determinations. The calculations are being extended to small molecules (H2, CH4), as well as to the study of the interaction of Rg atoms with porous graphene.