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Q: Fachverband Quantenoptik und Photonik
Q 53: Precision Spectroscopy of Atoms and Ions IV (joint session A/Q)
Q 53.6: Vortrag
Donnerstag, 5. März 2026, 12:30–12:45, N 3
The long range validity of the Wigner law - experimental test on negative oxygen — •Thorben Niemeyer1, Oliver Forstner2,3,4, Vadim Gadelshin1, Raphael Hasse1, Lothar Schmidt5, Markus Schöffler5, Matou Stemmler1, Dominik Studer1, and Klaus Wendt1 — 1Johannes Gutenberg-Universität Mainz — 2Friedrich-Schiller-Universität Jena — 3GSI Darmstadt — 4Helmholtz Institut Jena — 5Johann Wolfgang-Goethe Universität Frankfurt am Main
Negative atoms are quantum systems in which an additional electron is bound to the neutral core because of electron correlation effects. Correspondingly, its binding energy is one of the most fundamental properties and its knowledge is important for understanding those fragile quantum systems. The detachment of the additional electron by a photon via laser-ion interaction is a well-established measurement technique. It was recently performed on negative oxygen ions at the Frankfurt Low-energy storage ring FLSR. While the cross section curves near the energy threshold obtained in those kinds of measurements are typically well described by the Wigner law, the description further off from thresholds demands a more elaborate theory.
The measured detachment curve on negative oxygen comprises six photodetachment channels distributed over about 50 meV. We discuss the description of the combined threshold curve, in the Wigner appraoch in comparison to the more refined zero-core contribution theory.
Keywords: Negative ions; Photodetachment; Wigner law; Frankfurt Low-Energy Storage Ring