类锂离子双电子复合过程中辐射光子角分布和极化特性的理论研究

Theoretical study on angular distribution and polarization characteristics of X-ray emission following dielectronic recombination of lithium-like ions

基于多组态Dirac-Fock方法和密度矩阵理论,本文详细计算了高电荷态类锂离子(26 Z 92)KLL双电子复合过程中,自由电子被共振俘获到中间双激发态1s2s22p3/2J=1的磁子能级截面以及该双激发态的取向参数,进而得到了此激发态向基态电偶极辐射跃迁1s2s22p3/2J=1→1s22s2J=0所发出光子的角分布和极化度,重点讨论了Breit相互作用对相关物理量的影响.研究表明,Breit相互作用极大地改变了中间双激发态1s2s22p3/2J=1不同磁子能级的截面,从而导致了随后退激发放出光子的角分布和极化特性的显著变化.

Based on the multiconfiguration Dirac-Fock method and the theory of density matrix, we have calculated the magnetic sublevel captured cross section of intermediate doubly-excited state 1s2s22p3/2J = 1 formed by dielectronic recombination of lithium-like ions （26 ≤ Z ≤ 92）. Then, we obtain the angular distribution and linear polarization of X-rays of electric-dipole radiation 1s2s22p3/2J = 1→1s22s2J = 0. In this study, emphasis is placed on the effects of the Breit interaction on the relevant physical quantities. We find that the influences of the Breit interaction on the alignment for the capture to the doubly-excited state 1s2s22p3/2J = 1 are dramatic, resulting in the remarkable change in the angular distribution and polarization properties of the X-ray emission.