Theory of X-Ray Anisotropy and Polarization Following the Dielectronic Recombination of Initially Hydrogen-Like Ions
SHI Ying-Long1,2, DONG Chen-Zhong1**, FRITZSCHE Stephan3, ZHANG Deng-Hong1, XIE Lu-You1
1 Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 2College of Physics and Information Science, Tianshui Normal University, Tianshui 741001 3GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt D-64291, Germany
Abstract：The angular distribution and polarization of the x-ray photoemission of highly charged helium-like ions is studied following the K–LL dielectronic recombination of initially hydrogen-like ions. Calculation is carried out within the framework of the density matrix theory combined with the multiconfiguration Dirac–Fock approach. Attention is paid to magnetic sublevel alignment in the resonant intermediate state and to its nonuniform radiative decay processes. It is shown that the Breit interaction between the incident and target electrons plays a significant role for the alignment of the resonant state and thus causes a substantial change in the x-ray emission characteristic, when compared to the incorporation of only the (non-relativistic) Coulomb interaction. The most prominent difference in alignment parameter is found in the 2s2p1/2 J=1 resonant state for a wide range of atomic numbers from 9 to 92. For this resonant state of helium-like ions, the Breit interaction becomes significant for ions with nuclear charge Z～30 already.
2013, Vol. 30 
