Due to the very large number of electronic transitions computed for each system, the representation of the σ 0→n and Γ 0→n indexes over the 2 to 6 eV region is depicted as Gaussian convolutions. More precisely, the center of each Gaussian function is the energy of the electronic transition while its area is proportional to the index value in the limit of a used defined imposed threshold. In the following, only σ 0→n and Γ 0→n values above 40 and 90% will be retained, respectively. Both thresholds are chosen to minimize the noise and better identify the nature of the band.