Influence of Breit interaction on the polarization of radiation following inner-shell electron-impact excitation of highly charged berylliumlike ions

摘要

Electron-impact excitation cross sections from the ground state to the individual magnetic sublevels of the excited state 1s2s~22p_(1/2)J = 1 for highly charged berylliumlike ions have been calculated by using a fully relativistic distorted-wave (RDW) method. The degrees of linear polarization of the corresponding radiations are obtained. It is found that the Breit interaction makes the linear polarization of radiations decrease, and this character becomes more evident with increasing of incident electron energy. For a given energy in threshold units,the linear polarizationwithout the Breit interaction included increases very slowly as the atomic number increases,however, the linear polarization with the Breit interaction included decreases rapidly. These characteristics are very different from the conclusions for the linear polarization of the same radiations but formed by the dielectronic recombination process [Phys. Rev. Lett. 103, 113001 (2009)], in which the Breit interaction makes the linear polarization increase, and the linear polarization with the Breit interaction included increases with increasing of the atomic number.