Frankfurt 2006 – wissenschaftliches Programm

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A: Atomphysik

A 22: Poster II: Photoionisation

A 22.8: Poster

Donnerstag, 16. März 2006, 16:30–18:30, Labsaal

Linear polarization of the 2p⁵ 3s → 2p⁶ fluorescence light following the inner–shell photoionization of sodium–like ions — •S. Fritzsche¹, A. Surzhykov², M. K. Inal³, and G. Gaigalas⁴ — ¹Universität Kassel, D–34132 Kassel, Germany — ²Max–Planck–Institut für Kernphysik, D–69117 Heidelberg, Germany — ³Université A. Belkaid, 13000 Tlemcen, Algeria — ⁴Vilnius University Research Institute of Theoretical Physics and Astronomy, Vilnius, Lithuania

The inner–shell photoionization of multiple– and highly–charged, sodium–like ions has been studied theoretically by using multiconfiguration Dirac–Fock wave functions [1]. In these investigations, attention was paid especially to the linear polarization of the characteristic x–ray radiation emitted in the subsequent decay of the 2p hole state. Detailed calculations have been carried out for the 2p ⁵ 3s  →  2p ⁶ radiative transitions for sodium–like Fe ¹⁵⁺ and U ⁸¹⁺ ions. From the comparison of our calculations, based on the electric dipole approximation and the full relativistic theory, we found that the higher multipoles of the radiation field lead to an enhancement of the linear polarization for U ⁸¹⁺ but to a reduction for the Fe ¹⁵⁺ ions [2]. The most pronounced depolarization effect for the Fe ¹⁵⁺ ions appears for the 2p⁵3s    ³P₁ → 2p^{6   1}S₀ decay where the Stokes parameter P_L ^E1 decreases by more than 30 % if the non–dipole terms in the photoionization cross sections are taken into account.

[1] S. Fritzsche, J. Electr. Spec. Rel. Phenon. 114–116, 1155–64 (2001).

[2] M. K. Inal, A. Surzhykov and S. Fritzsche, Phys. Rev. A72, 042720 (2005).