In recognition of the above, even though both lycopene and β-carotene possess an 11 linear conjugated  bond system, but because they are centrosymmetric, half of their molecular orbitals 'degenerate'. To this end, lycopene and β-carotene behave as if they only have a five or six conjugated  bonds which is well in agreement with the empirical observations i.e. they appear as an orangish-red pigments. In contrast, a non-centrosymmetric polyene such as flavoxanthin with an eight linear conjugated  bond system (Fig. appears exclusively as a bright yellow solid. This might seem a bit puzzling as the longer a conjugated system, the longer its  max . However, even though the gaps between the ungeraden and geraden molecular orbitals of flavoxanthin should be smaller than say, that of lycopene, but because the energy levels are getting much closer, then the fundamental electronic excitation is no longer S 0 → S 1 and higher energy excitations will have a much higher transition probability to an extent that they preponderate over the lowest energy excitation, and hence flavoxanthin absorbs blue light, but lycopene absorbs the lower energy blue-green light. Equally, whatever concoction in the literature 6 has been ascribed to 1 must have absorbed the higher energy blue light, hence the resulting yellow compounds; nevertheless, in contrast to the literature precedents, as delineated above, the true puriss. or even purum samples of 1 are intrinsically orangish in colour (Fig. ).