The structure behind it all

Abstract

The talk discussed collisions where the structure of the systems involved plays a decisive role for the outcome of the event. For many types of charge changing processes the presence of resonant states can change the probability for a certain reaction by orders of magnitude. One example of this is electron-ion recombination where the resonant states are doubly or even multiply excited states lying above the ionization threshold of the recombined ion. The concept of a resonant state is discussed with the help of a simple model. The in uence of such states is then illustrated through a few examples where some di erent calculational methods are compared with experiments. Finally, the possibility to also obtain accurate spectroscopical information from a collisional process is discussed