Cross Section Data for Electron Impact Excitation of Xe II

To meet the demands of spectral analysis and collisional-radiative modeling for the Xe plasma, an extensive theoretical calculation of the electron impact excitation of singly-ionized xenon (Xe II) has been carried out. We employed the fully relativistic Dirac B-spline R-matrix (DBSR) method to deal with the complicated open 5p-shell structure of Xe II and the subsequent electron scattering problem. A total of 67 low-lying fine-structure levels of \(5s^25p^5\), \(5s5p^6\), \(5p^46s\), \(5p^45d\), \(5p^46p\) and \(5p^47s\) configurations were included in the close-coupling expansion. Following our previous study Plasma Sources Sci. Technol. 28 105004 (2019), we modestly refined the configuration-interaction (CI) expansions of the target model to improve both the agreement between the calculated fine-structure level positions and the NIST values, and the convergence of the radiative transition parameters. Comprehensive sets of cross sections for the electron impact excitations between those levels were reported, including the updated integral cross sections for incident energies from threshold to 100 eV, as well as the newly added differential cross sections between 20 and 30 eV. Subsequently, effective collision strengths were derived using a Maxwellian distribution over a broad temperature range from \(10^2\) to \(10^6\) K. Radiative transition parameters were also provided for all possible electric dipole-allowed transitions between the target levels. The consistency of the radiative transition parameters is observed between the length-form and the velocity-form, and the convergences with respect to the CI expansions, the target states, and the partial-wave expansions were carefully tested. Comparison with data from other works shows agreement. The present calculations addressed the scarcity of radiative and electron-collisional data for Xe II, and the full datasets are openly available in the Science Data Bank.