  The HOMO-LUMO gaps of the bilayer fullerene onions were investigated. For
this purpose, the HOMO and LUMO energies were calculated for the isolated
fullerenes using the parametrization of the tight binding method with the
Harrison-Goodwin modification. Next, the difference of the Fermi levels of the
outer and inner shell was calculated by considering the hybridization of the
orbitals on the base of the geometric parameters. The results were obtained by
the combination of these calculations.
