DEPENDENCE OF BINDING-ENERGY ON THE NUMBER OF ATOMS FOR CARBON FULLERENES

Using a molecular orbital method with non-local-density and Harris-fun ctional approximations, the bond lengths, binding energies and HOMO-LU MO energy gaps of the carbon fullerenes C(n) have been calculated on t he assumption that all bond lengths in each fullerene are the same. Th e results are as follows. (1) The binding energies (per atom) of C(n) containing hexagonal and pentagonal rings are expressed as F-A/n, wher e F and A are the binding energy (per atom) of an infinitely long carb on fullerene and the excess strain energy of pentagonal rings, respect ively. (2) The values of A for C(n) (n=24-36) are larger than those fo r C(n)(n=60-120), because of the adjoining pentagonal rings in the for mer. (3) C60, C70, C100, C90, C32 and C120, in decreasing order, have especially large HOMO-LUMO energy gaps and are expected to be less rea ctive.