The Post-collision Interaction in Ionization by Ion Impact

The most important goal of research in ion–atom collisions is to advance our understanding of the few-body problem. In perturbation theory understanding, the few-body dynamics means accurately describing the relative importance of the contributions from the various first- and higher order contributions to the process of interest. One higher order mechanism which often plays a prominent role is known as post-collision interaction (PCI). Since its signatures were discovered in the ejected electron spectra, they were also found in cross sections differential in kinematic parameters of the scattered projectile and the recoiling target ion. More recently, numerous fully differential measurements were reported. In this chapter, the progress achieved by these experiments and theoretical calculations are reviewed.