Angle-resolved electron–electron and electron–ion coincidence spectroscopy: new tools for photoionization studies

The development of two new experimental methods in gas phase photoionization studies is reviewed. These are angle-resolved electron–electron coincidence spectroscopy and angle-resolved electron–fragment ion coincidence spectroscopy. The review concentrates on systems which employ time-of-flight techniques for both the electron and ion detections. In addition to a technical description of such a system for both methods, showcase examples of their application in synchrotron radiation-based atomic and molecular physics are presented and discussed