First-Principles Study of Nucleic Acid Bases Physisorbed on Graphene

We report the results of our investigation on the interaction of nucleic acid bases bases with graphene, carried out within the density functional theory framework, with additional calculations utilizing Hartree--Fock plus second--order M{\o}ller--Plesset perturbation theory. The calculated binding energy of the five nucleobases shows the following hierarchy: G $>$ T $\approx$ C $\approx$ A $>$ U, though the equilibrium configuration consists of nearly the same separation between the sheet and the bases considered. The stabilizing factor in the interaction between the nucleobases and the graphene sheet appears to be dominated by the molecular polarizability that induces a weakly attractive dispersion force between them. The present study is a first step toward understanding why different DNA sequences interact differently with CNTs, as observed experimentally.