To apply the Hückel's model expressions (Equations 18 and 24), we also need an estimation of the coupling strength of the sp 2 -hybridized orbitals, given as parameter B in Equations 18 and 24. To obtain such an expression, the Equation 14 was fitted to the quantum-chemically computed values of polyenes, giving IP ∞ = 5.4 ± 0.1 [eV] and B = 16.1 ± 0.7 [eV]. The second parameters, D poly and D annu , were taken as the means of the dissociation energies of the neutrals of all computed sizes. The values for both polyenes and annulenes approach some limit, therefore justifying such an operation. The oscillations of the dissociation energies for polyenes arise from the alternating middle bond being either a formally single or double bond (see Figure ). The resulting values were D poly = 6.5 ± 0.7 [eV] and D annu = 12.3 ± 0.5 . Note that D annu ≈ 2 × D poly , because two carbon-carbon bonds are being broken during the dissociation of the annulene.