Electron-impact excitation of ions: Experimental status and perspectives

Abstract

The development of new experimental techniques based on electron energy‐loss spectroscopy and of powerful new ion sources and devices has facilitated more detailed quantitative studies of electron‐impact excitation of positive ions than have heretofore been possible. Data for angular differential as well as total cross sections are providing more stringent tests of the theoretical approximations used for such collisions, and some new insights into the excitation process. Extremely precise measurements of electron‐impact ionization cross sections have also revealed rich structures due to inner‐shell excitation and resonant excitation processes. An overview is presented of the current status and outlook of experimental studies of electron‐impact excitation of positive ions.