Research on photon and electron collisions with atomic and molecular targets and their ions has seen a rapid increase in interest, both experimentally and theoretically, in recent years. This is partly because these processes provide an ideal means of investigating the dynamics of many particle systems at a fundamental level and partly because their detailed understanding is required in many other fields, particularly astrophysics, plasma physics and controlled thermonuclear fusion, laser physics, atmospheric processes, isotope separation, radiation physics and chemistry and surface science....