Stuttgart 2012 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 23: Poster: Electron scattering and recombination
A 23.3: Poster
Dienstag, 13. März 2012, 16:30–19:00, Poster.V
Unexpected high strength of intershell trielectronic recombination — •C. Beilmann1, P.H. Mokler1, S. Bernitt1, C.H. Keitel1, J. Ullrich1, J.R. Crespo López-Urrutia1, and Z. Harman1,2 — 1Max-Planck-Institut für Kernphysik, Heidelberg, Germany — 2ExtreMe Matter Institute (EMMI), Darmnstadt, Germany
Intershell KL-LLL trielectronic recombination (TR) in highly charged ions, where a K-shell and a L-shell electron are simultaneously excited by the capture of a free one, was supposed to occure in neglectible strength due to the large excitation energy and a weak electron-electron interaction in inter-shell processes. In our experiments and accompanying ab initio MCDF calculations, we show that these higher order contributions to the total recombination yield grow to an unexpected strength in light and mid-heavy ions. The experimental results of TR measurements in Ar, Fe and Kr allow for the deduction of a scaling law for the TR strength in dependence of Z. In C-like ions with Z ≤ 20, TR even dominates over the first order dielectronic process [1]. These surprising findings should be taken into account in the detailed modelling of astrophysical and fusion plasmas. This is important in view of the problem of missing opacities in calculations of the solar matter and can also help improving plasma diagnostics of laboratory plasmas. Furthermore, the strong sensitivity of the TR process to eletron-electron interaction gives new experimental access to the study of inner-atomic electron correlation effects.
[1] C. Beilmann et al., Phys. Rev. Lett. 107, 143201 (2011)