Double Ionization of Helium by Electron Impact: A Study of the Two-Step Mechanism

  • Claude Dal Cappello
  • Rachid El M’Khanter
  • Pascal Lamy
Part of the Physics of Atoms and Molecules book series (PAMO)


The study of the double ionization of atoms or molecules by electron impact is a powerful tool in investigating finer details of the ionization process. This double ionization by electron impact is due to different processes:
  • direct process consisting to a simultaneous double ionization of two electrons via different mechanisms

  • indirect process resulting of an ionization of a single inner-shell electron followed by Auger decay

  • resonant processes in collisions with positive ions referred to as-called resonant excitation-autoionization process which lead to a final emission of three electrons (the incident one is captured by the target ion and ejected with two target electrons).

We restrict here to the double ionization of helium by electron impact which only involves direct process.


Scattered Electron Incident Electron Born Approximation Double Ionization Target Electron 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer Science+Business Media New York 1997

Authors and Affiliations

  • Claude Dal Cappello
    • 1
  • Rachid El M’Khanter
    • 1
  • Pascal Lamy
    • 1
  1. 1.Laboratoire de Physique Moléculaire et des CollisionsInstitut de Physique et d’Electronique de MetzMetz Cedex 03France

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