Electron-Impact Double Ionization of I1+ and Xeq+ (q=1, , 4) Ions: Role of 4d Electrons Like in Photoionization

Abstract
The cross sections for electron-impact double ionization of I1+ and Xe1+ ions (and to a lesser extent also of Xe2+, Xe3+, and Xe4+ ions) show a dominant resonancelike contribution which, both in shape and size, almost coincides with the partial 4d-photoionization cross section of Xe atoms.