Linear polarization polarization of the dielectronic recombination Kα satellite lines in Li-like Au76+

The degree of linear polarization of the dielectronic recombination K alpha satellite lines in Li-like Au76+ is obtained within the density matrix formalism based on the relativistic atomic data computed via relativistic distorted wave approximation. In the absence of accurate laboratory wavelength measurements for the K-shell resonance lines in gold ions, the atomic data for the He-like Au77+ target ion were computed in a systematic approach and compared with existing semi-relativistic Breit-Pauli calculations [S. Nahar, A.K. Pradhan, C. Sur, JQSRT 2008:109:1951]. The computation for the recombined Au76+ ion comprises 915 fine-structure levels arising from 1s(2)nl, 1s2snl, 1s2pnl, and 1s3l3l' configurations, with n <= 9 and l <= 4, l' <= 2, which yield 731 K alpha transitions of type 1s2pnl 1s(2)nl within 0.17486 to 0.18776 Aspectral range. The degree of linear polarization for the overall K alpha satellites as well as for each individual line is computed. Present results show how radiation from neighboring resonances gives peaks of local minima or maxima in the polarization when plotted against the kinetic energy of the incoming electron. Interference effects occurring for bright lines emitted from spatially close resonances result in depolarization of the radiation and displacement of the polarization peaks. Present quantitative results are useful for gold plasma diagnostics and fundamental physics. (C) 2018 Elsevier Ltd. All rights reserved.