München 2004 – wissenschaftliches Programm

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A: Atomphysik

A 15: Poster 2

A 15.9: Poster

Donnerstag, 25. März 2004, 14:00–16:00, Schellingstr. 3

Two–photon ionization of heavy atomic systems — •Andrey Surzhykov, Peter Koval, and Stephan Fritzsche — Universität Kassel, D–34132 Kassel, Germany

Multi–photon ionization processes have been studied in great detail during the last decade, both experimentally and theoretically. Until now, however, most of these studies remained focused on the ionization of outer–shell electrons because powerful laser sources in the EUV and X-ray region have not been available any way. The development of new synchrotron light sources have made it more likely to investigate the few–photon excitation/ ionization also for heavy atoms and ions like highly charged ions or atomic inner–shells [1].

In this contribution, we explore theoretically the two–photon ionization of heavy atoms. To understand the relativistic phenomena in two–photon ionization, we investigate hydrogen-like ions in the 2s–metastable state. Although, in the total cross sections, the relativistic behavior shows up only in a splitting of resonances and an overall decrease, the electron angular distribution may change qualitatively, in dependence on the photon energy. To reveal, in addition, the many–electron effects, the two–photon ionization of helium atom and argon K– and L–shells is considered. An interesting, unusual dependence of of the L–shell cross section on the polarization of light makes this shell a promising candidate for an experimental study of two-photon ionization.

[1] M. A. Kornberg, A. L. Godunov, S. I. Ortiz, D. L. Ederer, J. H. McGuire and L. Young, Journal of Synchrotron Radiation 9 (2002) 298.