Darmstadt 2008 – scientific programme

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A: Fachverband Atomphysik

A 29: Electron scattering and recombination

A 29.3: Talk

Friday, March 14, 2008, 11:45–12:00, 3D

Exploring correlated high-field few-electron QED by means of dielectronic recombination in W^69+...72+ ions — •Volkhard Mäckel, José Ramón Crespo López-Urrutia, Antonio Javier González Martínez, Zoltan Harman, Hiro Tawara, and Joachim Ullrich — MPI für Kernpysik, Saupfercheckweg 1, 69117 Heidelberg, Germany

The photorecombination of highly charged few-electron tungsten ions W⁶⁹⁺ to W⁷²⁺ has been investigated at the Heidelberg electron beam ion trap. By scanning the electron beam energy between 39 keV and 44 keV over the KLL dielectronic recombination region and monitoring the emitted x rays, the dielectronic resonance energies of the different charge states could be determined relative to the heliumlike resonances with an relative error as low as 3 eV at 40 keV. At this level of experimental accuracy quantum electrodynamic (QED) and finite nuclear size contributions can be probed. A comparison with different predictions shows strong discrepancies for certain Li- and Be-like ion states while general agreement with other charge states is found. This confirms earlier findings for mercury (Hg⁷⁵⁺ to Hg⁷⁸⁺) DR measurements [1,2].

[1] A. J. González Martínez et al., Phys.Rev. A 73 (2006) 052710

[2] Z. Harman et al., Phys Rev. A 73 (2006) 052711