Single and multiple ionization of neon and argon atoms by 3.6 MeV/u ${\mathrm{Au}}^{53+}$ impact has been explored in kinematically complete experiments. Doubly differential cross sections for low-energy electron emission have been obtained for a defined charge state of the recoiling target ion and the receding projectile. Observed target specific structures in the electron continuum are attributable to the nodal structure of the initial bound state momentum distribution. The experimental data are in excellent accord with continuum-distorted-wave eikonal-initial-state single ionization calculations if multiple ionization is considered appropriately.

• Received 24 May 1999

DOI:https://doi.org/10.1103/PhysRevLett.83.4721