Hilckel Molecular Orbital

For the series PhmMe3 mGe the ring proton hyperfine couplings increase as m decreases (Table 2), consistent with an increase in the unpaired spin density at the ring carbon atoms. Hilckel molecular orbital calculations bear this out8,14. Overall, however, the small values of the ring proton hyperfine couplings reveal that there is only a small Ge 4p-C 2p overlap in these radicals. 

The Hilckel molecular orbital method gives the following LCAOMO for the unpaired electron in the naphthalene negative ion ... 

In most applications these orbitals are chosen to be Hartree-Fock orbitals, though as will be noted below other types of orbitals (Hilckel orbitals, natural orbitals, or even nonorthog-onal orbitals) may also be used. Hereinafter, however, by orbitals we will mean HF orbitals, and since we are primarily interested in applications to molecules, we will also tacitly assume that they are molecular orbitals (MOs). 

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