▎ 摘　　要

Recently, graphene sheet is one of interesting systems to realize novel electronic properties. Especially, interaction between graphene and adsorbed oxygen molecule is very important to control electronic condition. In this paper, we employed some aromatic hydrocarbons as simple systems of graphene sheet and ab initio MO calculations were carried out to investigate inter-molecular interaction. It is found that not triplet but singlet O-2 molecule have potential of chemisorption onto graphene surface. From the calculated potential energy surface (PES) for distance between benzene and O-2 molecules, meta-stable structure is found at about 1.5 angstrom with potential barrier. In the optimized structure of its meta-stable state, structural strain can be relaxed through bending of planer benzene ring. Its energy is estimated at 70.10 kcal/mol for benzene. We also estimated the strain effects for naphthalene and pyrene molecules as larger case of graphene and they were 80.85 and 72.45 kcal/mol, respectively. (C) 2011 Elsevier Ltd. All rights reserved.