Berlin 2014 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 34: Precision spectroscopy of atoms and ions IV (with A)
Q 34.5: Talk
Thursday, March 20, 2014, 11:30–11:45, BEBEL SR140/142
EUV spectroscopy of Re, Os, Ir, and Pt near the 4f − 5s level crossing — •Hendrik Bekker1, Oscar O. Versolato2, Alexander Windberger1, Ruben Schupp1, Zoltan Harman1, Natalya Oreshkina1, Piet O. Schmidt2,3, Joachim Ullrich2, and José R. Crespo López-Urrutia1 — 1Max-Planck-Institut für Kernphysik — 2Physikalisch-Technische Bundesanstalt — 3Leibniz Universität Hannover
Understanding the electronic level structure of the 4f−5s crossing in highly charged ions is a challenging goal for both atomic theory and experiment. Complex electron correlations make calculations cumbersome, producing results with an accuracy which is not sufficient for unambiguous identification of the plethora of observed transitions. We employ an electron beam ion trap to prepare Re, Os, Ir, and Pt ions in charge states 13+ to 20+. Transitions in the extreme-ultra-violet (EUV) range are studied with a grating spectrometer. The first identification step is to determine the charge state to which the transitions belong. For that we apply two independent methods, yielding agreeing values. We then tentatively match observed transitions to atomic theory predictions. The results provide a benchmark for atomic theory in the area of highly correlated systems. A better understanding of the Ir17+ level structure is required for future laser spectroscopy studies of a possible variation of the fine-structure constant. Photon excitation measurements on the thus far observed transitions are planned at BESSY II.