We report on the possibility of describing the absorption and emission characteristics of an
ensemble of silicon nanocrystals (NCs) with realistic distributions in the NC size, by the sum of
the responses of the single NCs. The individual NC responses are evaluated by means of ab initio
theoretical calculations and the summation is performed by taking into account the trend of the
optical properties as a function of NC size and oxidation degree. The comparison with
experimental results shows a nice matching of the spectra, also without any tuning of the
parameters. Finally, the possibility of adapting the model in order to reproduce the experimental
data is explored and discussed.
