includes the bond-order-dependent covalent energy along with the short-range repulsion and hybridization terms, which vary with geometry and 2s population respectively, but are independent of the bond-order. The resonance stabilization of aromatic species can thus be directly calculated as the difference between the total BEBOP energy and the BEBOP energy of a hypothetical species with the same geometry and hybridization, but with the bond orders associated with the Lewis structures (Figure ):