Upper figure: the L + π − π ^⋆ , C6 and σ − σ^∗ component contributions to the imaginary part of the refractive index, k, for E_g(bulk) = 0.25 eV and radius 0.5 nm. Lower figure: the same data presented as (αE)^0.5. See text and previous figure for details.The black lines show the aromatic cluster profile extrapolations (determined by the open diamond data points) to the band gap values (thin grey vertical lines).