Erlangen 2018 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 25: Poster Session I
A 25.2: Poster
Dienstag, 6. März 2018, 16:15–18:15, Redoutensaal
Near L-edge single and multiple photoionization of singly charged iron ions — •Stefan Schippers1, Michael Martins2, Randolf Beerwerth3, Sadia Bari4, Kristof Holste1, Kaja Schubert4, Jens Viefhaus4,5, Daniel Wolf Savin6, Stephan Fritzsche3, and Alfred Müller1 — 1Univ. Gießen — 2Univ. Hamburg — 3Univ. Jena and HI Jena — 4DESY — 5HZB — 6Columbia Astrophysics Laboratory, New York, USA
Absolute cross sections for m-fold photoionization (m=1,…,6) of Fe+ by a single photon were measured employing the photon-ion merged-beams setup PIPE at the PETRA III synchrotron light source, operated by DESY in Hamburg, Germany. Photon energies were in the range 680–920 eV which covers the photoionization resonances associated with 2p and 2s excitation to higher atomic shells as well as the thresholds for 2p and 2s ionization. Supporting semi-relativistic and fully relativistic atomic-structure calculations are in good agreement with each other and with the experimental results. In particular, the complex deexcitation cascades after the creation of inner-shell holes in the Fe+ ion have been tracked on the atomic fine-structure level. The resulting theoretical product charge-state distributions are in much better agreement with the experimental data than previously published charge-state distributions from a configuration-average approach. The present experimental and theoretical results [1] are valuable for opacity calculations and are expected to pave the way to a more accurate determination of the iron abundance in the interstellar medium.
[1] S. Schippers et al., Astrophys. J. 849 (2017) 5.