High-resolution photoelectron-spectroscopy of radicals

The occurrence of radicals in various reactive environments and the importance of the ionization energy as a thermochemical property has motivated a large number of experiments on radicals using photoelectron-spectroscopy (PES). In this review we summarize and discuss PES of radicals performed at a resolution of better than 1 meV, with a focus on experiments applying zero kinetic energy (ZEKE)-spectroscopy and other methods based on the pulsed field ionization (PFI) of molecular Rydberg states. The basic physics of PFI, as well as the typical experimental set-up will be described. Subsequently the spectra of selected radicals will be discussed, emphasizing the scientific interest motivating the experiments. Particular attention is given to the methods used to generate the respective radical. (C) 2002 Elsevier Science B.V. All rights reserved.