▎ 摘　　要

First-Principles calculations were performed on the noncovalent interaction between graphene and aromatic heterocyclic molecules (thiophene, benzene, benzothiophene, dibenzothiophene, and pyridine) in the parallel and vertical orientations. The most stable adsorption configurations prefer pi - pi stacking way. The aromatic molecules are charge acceptors for graphenes. The polarity and the size of pi-conjugation can alter the magnitude of interactions between small aromatic molecules and graphene. According to the Hunter-Sanders model, we evaluate the relative contributions of pi-sigma attraction and the pi - pi repulsion. According to the adsorption energy and the differential electron density of the systems, it is found that the pi-sigma attraction energy accounts for the most portion of the adsorption energy.