Eur. Phys. J. Special Topics 169, 73-78 (2009)
https://doi.org/10.1140/epjst/e2009-00975-x

Multiple photoionization of atoms and small molecules by synchrotron radiation

¹ LCP-MR, Université Pierre et Marie Curie - Paris 6 and CNRS (UMR 7614), 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France
² Photon Factory, Institute of Materials Structure Science, Oho, Tsukuba, 305-0801, Japan
³ UVSOR Facility, Institute for Molecular Science, Okazaki, 444-8585, Japan
⁴ Japan Synchrotron Radiation Research Institute, Sayo, Hyogo, 679-5198, Japan
⁵ Physical and Theoretical Chemistry Laboratory, Oxford, OX1 3QZ, UK

Corresponding author: francis.penent@upmc.fr

Abstract

Absorption of one VUV photon by an atom or a molecule can induce the ejection of several electrons through different processes. Such multiple ionization processes, studied by coincidence electron spectroscopy, provide a wealth of information on electron correlations. A magnetic bottle electron time of flight spectrometer implemented on synchrotron radiation centers has allowed the efficient detection in coincidence of two, three and up to five electrons with good energy resolution. The branching ratios of the different processes are easily extracted from the experimental spectra due to the constant transmission of the spectrometer. Multiple Auger decay was observed in rare gases atoms after inner-shell ionization, while core-valence and core-core initial double ionization followed by Auger decay are other pathways to multiple ionization. For molecules, Coulomb explosion with energy released in ionic fragments may occur after multiple ionization, nevertheless, coincidence electron spectroscopy can also provide a clear interpretation for peculiar decay channels in molecules.