Semiempirical calculations on heterofullerene C59Si: structural and electronic localization

Si-doped heterofullerence C59Si is investigated via semiempirical PM3 calculations. Static geometric optimization shows that structural deformation occurs in the vicinity of dopant atom and gives rise to Si–C bonds significantly larger than the ordinary C–C bonds of the fullerene cage. Similar to the Kohn–Sham orbitals, the Hartree–Fock HOMO and LUMO are strongly localized on the dopant Si site. We find that the overestimation of the charges on Si and its nearest neighbor C atoms in previous semiempirical calculations is due to improper use of the MNDO method in calculating the Mulliken charge, and this problem can be solved by employing more accurate PM3 method.