Electronic Properties of Bilayer Fullerene Onions
  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. 
R. Pincak, V. V. Shunaev, J. Smotlacha, M. M. Slepchenkov and O. E.   Glukhova
cond-mat.mes-hall