Darmstadt 2008 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 25: Posters: Precision spectroscopy of atoms and ions

A 25.2: Poster

Donnerstag, 13. März 2008, 16:30–18:30, Poster C3

Polarization studies on the two–photon decay of hydrogen–like ions — •Andrey Surzhykov^1,2, Thomas Radtke³, Thomas Stöhlker^4,5, and Stephan Fritzsche^1,4 — ¹Max–Planck–Institut für Kernphysik, Heidelberg — ²École Normale Supérieure, Paris — ³Universität Kassel — ⁴Gesellschaft für Schwerionenforschung (GSI), Darmstadt — ⁵Universität Heidelberg

Since the early days of quantum mechanics, the two–photon decay of hydrogen–like ions has been the subject of intense experimental and theoretical studies. While, however, most investigations in the past dealt with the total transition probabilities, much of today’s interest is focused on the energy as well as angular distributions [1] and even on the polarization properties of emitted photons [2]. In the nearest future, for example, the two–photon polarization measurements are likely to be carried out at the GSI facility in Darmstadt. In order to provide theoretical support for these experiments, we present a density matrix formalism for the description of the (linear) polarization of one of the photons measured in coincidence with the second one. Based on this formalism and on the relativistic Dirac’s equation, detailed polarization calculations are performed for the 2s_1/2 → 1s_1/2 and 3d_5/2 → 1s_1/2 transitions in neutral hydrogen as well as in hydrogen–like xenon and uranium ions. The results of these computations show a strong dependence on the two–photon decay geometry as well as on the magnetic sublevel population of the excited ionic states.

[1] A. Surzhykov et al., Phys. Rev. A 71 (2005) 022509.

[2] H. Kleinpoppen et al., Phys. Scr. T72 (1997) 7.