We determined the ionic and electronic structure of sodium clusters with even electron numbers and 2 to 59 atoms in axially averaged and three-dimensional density functional calculations. A local, phenomenological pseudopotential that reproduces important bulk and atomic properties and facilitates structure calculations has been developed. Photoabsorption spectra have been calculated for $\mathrm{ Na}_2$, $\mathrm{ Na}_8$, and $\mathrm{ Na}_9^+$ to $\mathrm{ Na}_{ 59}^+$. The consistent inclusion of ionic structure considerably improves agreement with experiment. An icosahedral growth pattern is observed for $\mathrm{ Na}_{ 19}^+$ to $\mathrm{ Na}_{ 59}^+$. This finding is supported by photoabsorption data.
Categories: physics.atm-clus cond-mat.mtrl-sci physics.chem-ph