Semiconducting nanoparticles are the building blocks of optical nanodevices
as their electronic states, and therefore light absorption and emission, can be
controlled by modifying their size and shape. CdSe is perhaps the most studied
of these nanoparticles, due to the efficiency of its synthesis, the high
quality of the resulting samples, and the fact that the optical gap is in the
visible range. In this article, we study light absorption of CdSe
nanostructures with sizes up to 1.5 nm within density functional theory. We
study both bulk fragments with wurtzite symmetry and novel fullerene-like
core-cage structures. The comparison with recent experimental optical spectra
allows us to confirm the synthesis of these fullerene-like CdSe clusters