An extended Heisenberg model for conjugated hydrocarbons. II. Kekule basis

The valence bond (VB) model was implemented at a semiquantitative level through the extended Heisenberg model Hamiltonian. It was demonstrated that the improved VB model can be solved with reasonable accuracy in a very small basis, making it applicable to rather large molecules. Test calculations show that for benzoid hydrocarbons the Kekul basis can give a good semiquantitative description of ground-state energies, reaction energies, and singlet excitation energies. As an illustration of the use of the model for a chemical system whose size makes most computations beyond Hckel theory challenging, the ground and first excited state energies were computed for C60 buckminsterfullerene.

An extended Heisenberg model for conjugated hydrocarbons. II. Kekule basis Academic Article