Stuttgart 2012 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 9: Electron scattering and recombination

A 9.2: Vortrag

Montag, 12. März 2012, 16:45–17:00, V57.05

Angular correlations in radiative cascades following resonant electron capture — •Oliver Matula^1,2, Stephan Fritzsche^2,3, and Andrey Surzhykov^1,2 — ¹Physikalisches Institut, Universität Heidelberg, D-69120 Heidelberg — ²GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt — ³Department of Physical Sciences, University of Oulu, FI-90014 Oulu

Dielectronic recombination (DR) into highly charged ions has been studied intensively in the last decades, both in experiment and theory. Whereas in the past these studies dealt mainly with the total DR rates, much of today’s interest is focused on the angular properties of the characteristic x-ray photons. The angle-resolved investigations provide a unique tool to probe relativistic, many-body and QED effects in heavy atoms. For example, a strong E1-M2 multipole mixing in the radiative cascades following K-LL DR of U⁹¹⁺ has been recently identified by analyzing the angular distribution of the emitted hypersatellite (HS) photons. Apart from the individual HS and satellite (S) transitions, mixing phenomena may also significantly affect the angular correlations between the characteristic photons. In this contribution, we present a theoretical study of the γ-γ angular correlations for DR of highly charged ions, based on a density matrix approach and relativistic Dirac’s theory. Within this framework, we pay special attention to nondipole effects in the expansion of the electron-photon interaction. To illustrate these effects, detailed calculations will be presented for K-LL DR of (initially) hydrogenlike Xe, Au and U ions. Work is supported by the Helmholtz Gemeinschaft (Nachwuchsgruppe VH-NG-421).