Lahmam-Bennani, A., Taouil, I., Duguet, A., Lecas, M., Avaldi, L., Berakdar, J.
Origin of dips and peaks in the absolute fully resolved cross sections for the electron-impact double ionization of He
Physical Review A 59, pp 3548-3555 (1999)
Using a multiparameter multicoincidence spectrometer, we have measured the coplanar (e,3e) angular distributions following the double ionization of helium at an incident energy of ∼ 5.6 keV and under a small projectile's scattering angle of 0.45deg. The two ejected electrons have been detected with equal energies Eb=Ec=10 eV. The absolute value of the cross section is determined with an accuracy of 25 %. The origin of dips and peaks in the spectra is exposed by analyzing the corresponding theoretical calculations. These calcu-lations have been done using a four-body final-state wave function for the three electrons moving in the field of He2+. The dipolar limit is investigated and the manifestation of the deviation from this limit are pointed out. General features and possible trends for other targets are proposed.
TH-1999-07