Polarization of the Lyman line emission following radiative recombination of bare ions: effects of relativity and radiation multipoles

Detailed calculations using a fully relativistic distorted-wave method are carried out for the cross sections of longitudinally polarized electron impact excitation from the ground state to the magnetic sublevels of the 1s2p 3 2 = J (2) state of highly charged He-like ions. The relativistic effects on the cross sections and circular polarization of the x-ray photoemission are investigated in detail. For the excitation process, results show that the relativistic effects may become important leading to considerable enhancements in the cross sections. The inclusion of the relativistic effects can modify the cross sections by several orders of magnitude, especially to the M f = −1 and −2 magnetic sublevels. For the de-excitation process, the relativistic effects make the degree of circular polarization decreases, these features are more pronounced when the incident electron energy and/or atomic number increase. The relativistic effects are found to be much larger compared to the case of the linear polarization of radiation.

Section: Introductionmentioning

confidence: 95%

Relativistic effects on the cross section and circular polarization of x-ray radiation following longitudinally-polarized electron impact excitation of highly charged ions

Chen¹,

Zeng²,

Dong³

2015

“…On the other hand, such aligned target ions will be manifested in the polarization and the non-isotropic angular distribution of the characteristic x-rays [2]. From analysis of the polarization [3][4][5][6], valuable information can be obtained for a detailed diagnosis of the plasma state and analysis of the complex spectra formation.…”

Section: Introductionmentioning

confidence: 99%

“…They also dealt with the orientation and alignment generated from PI of closed-shell cations [17]. Inal et al [18] studied the alignment parameters and polarization properties of the  p s p 2 3 2 5 6 lines following inner-shell PI of Na-like ions within Dirac's relativistic approach. Yamaoka et al [19] calculated the alignment of Au + ions following PI of L 3 using the HF approximation and the random phase approximation with exchange.…”

Section: Introductionmentioning

confidence: 99%

Polarization transfer in x-ray transitions due to photoionization in highly charged copper-like ions

Chen

Xie

et al. 2018

Using the density matrix theory and the multi-configuration Dirac-Fock method, the d 3 3 2 subshell photoionization of highly charged ions is studied, together with their subsequent radiative decay. The effects of polarization transfer on the linear polarization and angular distribution of the  d s D d p P 3 4 3 4 9 2 2 3 2 10 2 1 2 characteristic line photoemission for selected Cu-like Zn + , Ba 27+ , + W 45 , and + U 63 ions are investigated. Our results show that the polarization transfer, arising from the originally polarized incident light, may lead to a considerable change in the alignment parameters and the polarization properties of the radiation, the character of which is highly sensitive to the initial photon polarization, yet virtually independent of the photon energy. These characteristics are very similar to those of the electron bremsstrahlung process reported by Märtin et al (2012 Phys. Rev. Lett. 108 264801). The present results are compared with available experimental results and show a good quantitative agreement.

“…ionization followed by the radiative de-excitation filling of an inner-shell vacancy induced by the impact of a photon, has practical implications in both astrophysical and laboratory plasmas. When compared to conventional observables, such polarization helps to reveal many details regarding the magnetic sublevel population [1][2][3][4][5], and, in fact, provides new insight for studying the electron-photon (e-ph) interaction during the dynamical process [6,7].…”

Section: Introductionmentioning

confidence: 99%

Relativistic effects on the linear polarization and angular distribution of x-ray radiation emitted by inner-shell photoionization of atoms

Ma¹,

Chen²,

Xie³

et al. 2017

We present a theoretical study of relativistic effects on the linear polarization and angular distribution of x-ray radiation for the La 2 (3 2 ) characteristic line following innershell single photoionization of Cd, Ba, Yb and Ra atoms. The analysis is performed based on the multi-configuration Dirac-Fock method and the density matrix theory. To explore the nature of these effects, calculations are carried out based on detailed analyses of the total and magnetic sublevel cross sections, the linear polarization, and the angular distribution of the x-ray photoemission, as well as on corresponding data calculated in the nonrelativistic limit. Our results show a significant difference in the above parameters compared to the nonrelativistic treatment, which is mainly due to the relativistic treatment of the target. Higher multipole contributions are also estimated, and found to be generally weaker. The importance of inclusion of the relativistic effects grows with increasing atomic number and the incoming photon energy.