A comparative study of the (e, 3e) process on H^-, He and Li⁺

Abstract

We present a comparative picture of the (e, 3e) process on H − , He and Li + . These three targets have isoelectronic structure with increasing nuclear Coulomb interaction. The study has been done at high incident energy, E 0 ≈ 5.6 keV, very small scattering angle and low ejected electron energies. The actual scattering angle is adjusted so that the momentum transfer and the energies of the ejected electrons are the same in all three cases. The result is that the final states are identical except for the charge on the bare nucleus. The value of the momentum transfer relative to the reciprocal of the atomic size is found to profoundly affect the angular distribution of the five-fold differential cross section.

Comment on ‘New geometry for the quasi-binary incident electron–centre of mass collision in the (e, 3e) process on He’

“…We have also considered the original LS within the 2CG model: the calculated FDCS, also multiplied by 200, are plotted but give different shapes (the same applies, for example, for BK14 (result not shown)). Our shape and magnitude observations are supported by another set of 2CG results, those of [17] (although a slightly different initial state was used and calculations were performed using effective charges which are practically equal to the normal ones for the kinematics under consideration). For example, for θ 1 = 319 • , the FDCS shown in figure 3 of [17] is very similar to ours: two symmetric peaks and a magnitude (maximum value of about 2 × 10 −5 ) needing a multiplying factor of 200 to be compared with the experimental data.…”

“…Our shape and magnitude observations are supported by another set of 2CG results, those of [17] (although a slightly different initial state was used and calculations were performed using effective charges which are practically equal to the normal ones for the kinematics under consideration). For example, for θ 1 = 319 • , the FDCS shown in figure 3 of [17] is very similar to ours: two symmetric peaks and a magnitude (maximum value of about 2 × 10 −5 ) needing a multiplying factor of 200 to be compared with the experimental data. The result presented in figure 4 of [1] shows the same absence of central peak; however, there seems to be a problem with the peaks' magnitude.…”

Comparative theoretical study of (e, 3e) on helium: Coulomb-waves versus close-coupling approach

“…An efficient and (in most cases) accurate way to describe a three-body Coulomb system is provided by the three Coulomb waves (3C) method (Brauner et al 1989). This method was applied to the (e, 3e) process on He by Joulakian et al (1992), Joulakian and Dal Cappello (1993), and most recently by Muktavat and Srivastava (2001). In the 3C theory the three-body system (the two slow electrons and the He 2+ ion) is broken down into three decoupled twobody subsystems.…”

Double ionization of the water molecule: Influence of the target orientation on the secondary-electron angular distributions

“…In addition, recent experiments on helium [17,18] (this target being the simplest two-electron system and then the best candidate for theoretical benchmarks) have renewed interest in (e,3e) studies (see, for example, the works of Dal Cappello and co-workers [19][20][21][22] for a review). Finally, note that additional interesting candidates such as H − and Li + ions have been recently proposed by Nath and Sinha [23] and Kshamata Muktavat and Srivastava [24] for studying, in particular, the role played by the incoming particle description (see, for example, Ref. [25] and references therein).…”