2018/02/19 by James R. Hamilton, James R Hamilton, Alexandre Faure +1
Earth and Planetary Sciences · Physics and Astronomy · #Adiabatic process #Astro and Planetary Science #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Atomic physics #Diatomic molecule #Dipole #Electron #Electron ionization #Excitation #Hydride #Hydrogen #Hyperfine structure #Ion #Ionization #Molecule #Physics #Quantum mechanics #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.1093/mnras/sty437
8 pages, 5 figures, 6 tables, accepted for publication in MNRAS
openalex publication_date 2018/02/19 · arxiv created 2018/02/21 · openalex created_date 2018/03/06 · arxiv updated 2018/03/14 · openalex updated_date 2026/08/06
R-matrix calculations combined with the adiabatic-nuclei-rotation and Coulomb-Born approximations are used to compute electron-impact rotational rate coefficients for two open-shell diatomic cations of astrophysical interest: the hydoxyl and sulphanyl ions, OH+ and SH+. Hyperfine resolved rate coefficients are deduced using the infinite-order-sudden approximation. The propensity rule ΔF = Δj = ΔN = ±1 is observed, as is expected for cations with a large dipole moment. A model for OH+ excitation in the Orion Bar photon-dominated region is presented which nicely reproduces Herschel observations for an electron fraction xe = 10−4 and an OH+ column density of 3 × 1013 cm−2. Electron-impact electronic excitation cross-sections and rate coefficients for the ions are also presented.