  We have investigated theoretically the adsorption of molecules onto graphene
with divacancy defects. Using ab-initio density functional calculations, we
have found that O2, CO, N2, B2 and H2O molecules all interact strongly with a
divacancy in a graphene layer. Along with a complex geometry of the
molecule-graphene bonding, metallic behavior of the graphene layer in presence
of CO and N2 molecules have been found with a large density of states in the
vicinity of the Fermi level suggesting an increase in the conductivity. The
adsorption of N2 is particularly interesting since the N atoms dissociate in
the vicinity of the defects, and take the place where the missing C atoms of
the divacancy used to sit. In this way, the defected graphene structure is
healed geometrically, and at the same time doped with electron states.
