Abstract : R-matrix calculations combined with the adiabatic nuclei approximation are used to compute electron-impact rotational excitation rates for three closed-shell diatomic cations, HeH+, CH+, ArH+. Comparisons with previous studies show that an improved treatment of threshold effects leads to significant changes in the low temperature rates; furthermore the new calculations suggest that excitation of CH+ is dominated by ΔJ = 1 transitions as is expected for cations with a large dipole moment. A model for ArH+ excitation in the Crab nebula is presented which gives results consistent with the observations for electron densities in the range 2-3 × 103 cm-3.
https://hal-insu.archives-ouvertes.fr/insu-03691576 Contributor : Nathalie POTHIERConnect in order to contact the contributor Submitted on : Thursday, June 9, 2022 - 11:49:55 AM Last modification on : Saturday, June 25, 2022 - 3:06:19 AM
James R. Hamilton, Alexandre Faure, Jonathan Tennyson. Electron-impact excitation of diatomic hydride cations - I. HeH+, CH+, ArH+. Monthly Notices of the Royal Astronomical Society, 2016, 455, pp.3281-3287. ⟨10.1093/mnras/stv2429⟩. ⟨insu-03691576⟩