Electronic structures and large spectrum shifts in hydrogenated fullerenes: Density functional theory study

•Hydrogen atom addition to C60 was investigated.•First hydrogen atom addition proceeded with very low activation barrier.•Second hydrogen addition was dependent on the binding site.•Addition site of second atom was correlated with spin density.

Electronic structures and band gaps of hydrogenated fullerenes have been investigated by means of density functional theory method. The mechanism of hydrogen addition reaction to the fullerene (C60) surface was also investigated. Addition of one and two hydrogen atoms was examined in the calculations. The binding energies of the second hydrogen atom to C60H were widely distributed in the range 1.5–3.6 eV. It was found that the bonding energy is strongly dependent on the spin density of carbon atom of C60H. The second hydrogen atom preferentially binds to the neighbor site of the first addition site. The electronic states and excitation energies of C60-H were discussed on the basis of theoretical results.