Ionic and electronic structure of sodium clusters up to N=59

We determined the ionic and electronic structures 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 Na-2, Na-8, and Na-9(+) to Na-59(+). The consistent inclusion of ionic structure considerably improves agreement with experiment. An icosahedral growth pattern is observed for Na-19(+) to Na-59(+). This finding is supported by photoabsorption data.