Magic clusters Na57- and Na59+

The electronic structure of positively charged sodium cluster with 59 atoms and negatively charged sodium cluster with 57 atoms (both having 58 electrons) have been studied using an ab initio molecular dynamics method. Both clusters show clearly the shell structure of the jellium model. Although the geometries of both clusters are nearly spherical, the results show differences in the electronic shells: -) the energy gaps between the jellium subshells are different, -) in Na57- the magic number 20 disappears and is replaced with a new magic number 18