Electron-impact excitation rate-coefficients and polarization of subsequent emission for Ar+ ion

•Fully relativistic distorted wave theory has been used to study the excitation of fine-structure states of Ar+.•We have calculated electron-impact excitation cross-sections for the wide range of incident electron energies.•Electron impact excitation rate-coefficients are calculated as a function of electron temperature.•Polarization of photons emitted following the decay of the excited fine-structure states are also reported.

Electron impact excitation in Ar+ ions has been studied by using fully relativistic distorted wave theory. Calculations are performed to obtain the excitation cross-sections and rate-coefficients for the transitions from the ground state 3p5 (J=3/2) to fine-structure levels of excited states 3p44s, 3p44p, 3p45s, 3p45p, 3p43d and 3p44d. Polarization of the radiation following the excitation has been calculated using the obtained magnetic sub-level cross-sections. Comparison of the present rate-coefficients is also done with the previously reported theoretical results for some unresolved fine structure transitions.