First Principles Study of Photoelectron Spectra ofCun−Clusters

We have determined equilibrium geometries and electronic properties of neutral and anionic ${\mathrm{Cu}}_n$ $(n=2,9\mathrm{})$ clusters by means of first principles calculations in which $s$ and $d$ electrons are treated on equal footing. We find that the calculated electronic density of states is inadequate to interpret photoelectron spectra of ${\mathrm{Cu}}_n^{-}$ clusters. We obtain good agreement between calculated excitation energies and experimental spectra when we include final states effects.