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

Abstract

In a recent publication, Choubisa and Sud (2008 Journal of Physics B: At. Mol. Opt. Phys. 41 035202) investigated (e, 3e) processes and compared their calculations with available absolute experimental data. According to the authors, the results (within the first and second Born approximation) were obtained using the 3C model for the final double-continuum state and two different helium ground initial states. As all these model wavefunctions are not properly defined, the paper introduces confusing ideas that need to be clarified to the community. In particular, we show here that they do not use the 3C model, but an approximate version which largely underestimates the cross sections. Furthermore, the authors propose an interesting new geometry, but again present peculiar results that must be clarified.

Angular distributions in the double ionization of argon by fast electron impact

“…The absolute scale for the data was determined [1] to within a factor of 2 and it is not known in what proportions the three states of the ion contribute to the FDCS. On the other hand, we know that the 2CWG models do not give the right amplitude [48] and our objective in this work will be to find a model that is able to reproduce the right trends in the FDCS.…”