Abstract. The dependence of electron capture and ionization processes on the pre-collision electronic distribution is examined for the systems primarily in the energy range 1 - 15 keV. Populations of the capture and ionization channels as well as the coherence of the post-collision electronic distribution of the capture product are formulated using the classical trajectory Monte Carlo (CTMC) method. Total capture and ionization cross sections arising from initially aligned Na(3p) targets exhibit transient behaviour near the velocity-matching energy of 5.7 keV. This observation is described in terms of anisotropy parameters; anisotropy effects are also analysed for the capture states n = 2, 3 and 4. In addition to the population manifold, we present theoretical calculations of the alignment parameter and the z-component of the dipole moment , in order to relate the alignment of the post-collision charge cloud to that of the initial Na(3s, , ) target states. The z-component of the cross product of the angular momentum and the Runge - Lenz vector is used to describe the orientation of the post-collision product generated from the aligned Na(, ) pre-collision reactants.

Print publication: Issue 9 (14 May 1996)
Received 27 November 1995, in final form 1 January 1996