Influence of adsorption of atoms and molecules of oxygen on the electronic structure of graphene nanoribbons

The article presents the results of calculations of the energy characteristics of adsorption of oxygen atoms and molecules on graphene nanoribbons surface. The calculations of electronic structures were carried out by semi-empirical MNDO and PM3 quantum-chemical methods using the molecular cluster model with boundary pseudoatoms. The main geometrical and electronic-energy characteristics of graphene nanoribbons with adsorbed oxygen atoms and molecules were calculated.
It is revealed that the changes of the frontier energies $E_{HOMO}$ and $E_{LUMO}$ indicate that the properties of nanoribbons depend on the result of adsorption, in particular, on the increase of these systems reactivity.
It is also revealed that an oxygen molecule is weakly bound to the GNR surface with low adsorption energy. The configuration where the oxygen atom is located above the center of the С-С bond, or directly above the carbon atoms of the surface of the GNR has a stronger binding between an oxygen and surface.