Electron emission in ionization of He by the impact of dressed and bare ions

Double-differential cross sections (DDCS) as a function of low-energy electron emission at different impact energies are calculated for the collisions of dressed ions with He atoms by using the four-body formalism of the three-Coulomb wave (3CW-4B) model. We report the energy distribution of ejected electrons with energies varying from 5 to 500 eV for different emission angles. In this work, a model potential is used to represent the interaction between the dressed projectile and the active electron of the target. This potential presents a short-range term and a Coulomb long-range term depending on the net charge of the projectile and the number of electrons bound to it. The nine-dimensional integrals for the transition amplitude are partly reduced to a two- and three-dimensional integrals, which can be easily calculated numerically. The present 3CW-4B results are compared with the available experimental data and other theoretical calculations. The results agree favorably well with the existing experimental findings, especially at high-impact energies. We also studied the dependence of the effective charge of the dressed projectile on the electron emission spectra. Furthermore, the DDCS has been calculated in a range of projectile scattering angles (0–2 mrad) along with electron energies (10–300 eV) and discussed the appearance of different structures.