Anisotropic distributions of the Lyman-${\alpha }_1$ transition of the down-charged $\mathrm{X}{\mathrm{e}}^{53+*}$ ions are observed in fast $\mathrm{X}{\mathrm{e}}^{54+}$ with Kr and Xe collisions, in which the electron is transferred by the nonradiative electron capture mechanism. At the energy of 95 MeV/u, the alignment parameter of the projectile $2p_{3/2}$ state, ${\mathcal{A}}_{20}$, is determined to be −0.35 ± 0.02 for both targets. While the projectile energy is 146 MeV/u, the parameter for the Kr and Xe target is −0.28 ± 0.02 and −0.29 ± 0.04, respectively. The present results demonstrate that the electron capture to the $m_j=\pm 1/2$ magnetic substates is about two times more probable than to the $m_j=\pm 3/2$ ones.

• Received 8 July 2020
• Revised 24 August 2020
• Accepted 8 September 2020

DOI:https://doi.org/10.1103/PhysRevA.102.042803