Erlangen 2018 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 27: XUV/X-ray Science
A 27.7: Vortrag
Mittwoch, 7. März 2018, 15:30–15:45, K 1.011
Auger cascade calculations for astrophysically relevant ions — •Randolf Beerwerth1,2, Sebastian Stock1,2, Stefan Schippers3, and Stephan Fritzsche1,2 — 1Helmholtz Institut Jena, 07743 Jena — 2Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universität Jena, 07743 Jena — 3I. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Giessen
We performed Auger cascade calculations to model the deexcitation pathways that follow upon direct ionization or resonant excitation of inner shell electrons. By building the complete deexcitation trees, we can compute cross sections and ion yields that are useful for e.g. plasma modeling in astrophysical applications. Of special importance for these applications are several isotopes of iron, which are the target of experimental campaigns with the photon-ion merged-beams setup PIPE [1]. We present our calculations for the multiple ionization of Fe1+ and Fe3+, where experimental data is available [1, 2] as well as for Fe2+, where an experimental campaign is planned.
Previous configuration average calculations are not in good agreement with the experimental results, which is resolved by our model at fine structure level. For higher charge states, several three electron Auger processes become crucial where an additional shake down transition provides a sufficient gain in energy for an additional Auger decay. Including such transitions drastically modifies the computed ion yields and leads to a good agreement with experimental results.
[1] S. Schippers et al., Astrophys. J. 849 (2017) 5.
[2] R. Beerwerth et al., submitted