Electron-momentum densities of singly charged ions

Spherically averaged electron momentum densities Pi(p) are constructed by t he numerical Hartree-Fock method for 54 singly charged atomic cations from He+ (atomic number Z = 2) to Cs+ (Z = 55) and 43 anions from H- (Z = 1) to I- (Z = 53) in their experimental ground state. As in the case of neutral a toms, the Hartree-Fock momentum densities for all these ions can be classif ied into three types; 28 cations and 10 anions have a unimodal density with a maximum at p = 0, 22 cations and 21 anions have a unimodal density with a maximum at p > 0, and 4 cations and 12 anions have a bimodal density with a primary maximum at p = 0 and a secondary maximum at p > 0.