Z. W. Wu,
Z. M. He,
Z. Q. Tian,
C. Z. Dong,
and S. Fritzsche
Angular and polarization properties of the Lyman-alpha(1) line 2p(3/2) -> 1s(1/2) following electron-impact excitation of hydrogenlike ions
Phys. Rev. A, 105 :062813 (June 2022)
Angular and polarization properties of the Lyman-alpha(1) line 2p(3/2) -> 1s(1/2) following electron-impact excitation of hydrogenlike ions
Phys. Rev. A, 105 :062813 (June 2022)
Abstract:
Electron-impact excitation from the ground state to the excited energy level 2p(3/2) of hydrogenlike ions and subsequent Lyman-alpha(1) (2p(3/2) -> 1s(1/2)) radiative decay are investigated using the relativistic distorted-wave method. Special attention is paid to the linear polarization and angular distribution of the Lyman-alpha(1) line and also to the effects of the Breit interaction. To this aim, detailed calculations are performed for hydrogenlike Ti21+, Mo41+, Ba55+, and Au78+ ions. It is found that the presently obtained (partial cross sections and) linear polarization agree excellently with other theoretical and experimental results available for low-Z Ti21+ ions within the experimental uncertainties. Moreover, the Lyman-alpha(1) line is found to be less linearly polarized and less anisotropic due to the contribution of the Breit interaction. Such effects of the Breit interaction behave more prominently for higher-Z ions and higher impact electron energies, respectively. For instance, the Breit interaction qualitatively changes the polarization behavior and angular emission pattern of the Lyman-alpha(1) line from high-Z Au78+ ions at the impact energy of about 4.2 times the corresponding excitation threshold.