Abstract
Within the last two years a number of highly refined measurements have been performed on H targets which have yielded accurate absolute data for a range of energies and geometries1 and it would appear that the experimental situation for this, the simplest of atomic targets is now resolved. The theoretical situation is however far from satisfactory and in this paper we will analysis some of the main approaches and characterise their strengths and their weaknesses. We have developed a numerical method which allows us to evaluate triple differential cross sections(TDCS) using the most complex position dependent analytic ansatz wave function and we will present results, using this for low energy (e,2e) processes. We will see that this approach fails when incident channel effects, such as target polarization, are likely to be strong. We will consider the alternative close coupling approach, known as the convergent close-coupling (CCC), and demonstrate that it fails to converge in symmetric geometries, where final state Coulomb 3 body interactions between the two free electrons and the nucleus are strong. We will compare both types of calculations with a simple distorted wave born approximation where these effects can be included in a straight forward way and the interactions switched “on” and “off” at will.
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Rasch, J., Whelan, C.T. (1999). Characteristics of Low Energy (E,2E) Processes. In: Whelan, C.T., Dreizler, R.M., Macek, J.H., Walters, H.R.J. (eds) New Directions in Atomic Physics. Physics of Atoms and Molecules. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-4721-1_39
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DOI: https://doi.org/10.1007/978-1-4615-4721-1_39
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