Coherent Excitation and Decay of Autoionizing States in Ion-Atom-Collisions

Excitation and decay of autoionizing states in slow ion atom collisions is studied by two methods: (i) by energy analysis of electrons, ejected in He+/He, He+/Ne and Ne+/Ne collisions at an ejection angle of ¿= 180° with respect to the beam direction, and (ii) by measurement of angular correlations between autoionization electrons and scattered ions in 2 keV He+/He collisions. It is shown that with a semiclassical description, which assumes coherent excitation of the autoionizing states and their magnetic sublevels the experimental data can be described quantitatively.