Weighted HOMO-LUMO energy separation as an index of kinetic stability for fullerenes

A very simple but general index of kinetic stability, T, is proposed for pi-electron systems, which is defined as a highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy separation multiplied by the number of conjugated atoms. This new index can be justified by relating it to the approximate form of the superdelocalizability, an index of chemical reactivity defined by Fukui et al. It is best suited for predicting the kinetic stability of fullerenes. All isolable fullerene isomers have T values larger than 13.