Hybridization-related correction to the jellium model for fullerenes
  We introduce a new type of correction for a more accurate description of fullerenes within the spherically symmetric jellium model. This correction represents a pseudopotential which originates from the comparison between an accurate ab initio calculation and the jellium model calculation. It is shown that such a correction to the jellium model allows one to account, at least partly, for the sp2-hybridization of carbon atomic orbitals. Therefore, it may be considered as a more physically meaningful correction as compared with a structureless square-well pseudopotential which has been widely used earlier. 
A. V. Verkhovtsev, R. G. Polozkov, V. K. Ivanov, A. V. Korol, A. V.   Solov'yov
physics.atm-clus