Excitation and charge transfer in low-energy hydrogen atom collisions with neutral carbon and nitrogen

Abstract

Low-energy inelastic collisions with neutral hydrogen atoms are important processes in stellar atmospheres, and a persistent source of uncertainty in non-LTE modelling of stellar spectra. We have calculated and studied excitation and charge transfer of C i and of N i due to such collisions. We used a previously presented method that is based on an asymptotic two-electron linear combination of atomic orbitals (LCAO) model of ionic-covalent interactions for the adiabatic potential energies, combined with the multichannel Landau-Zener model for the collision dynamics. We find that charge transfer processes typically lead to much larger rate coefficients than excitation processes do, consistent with studies of other atomic species. Two-electron processes were considered and lead to non-zero rate coefficients that can potentially impact statistical equilibrium calculations. However, they were included in the model in an approximate way, via an estimate for the two-electron coupling that was presented earlier in the literature: the validity of these data should be checked in a future work.

arXiv comment11 pages, 5 figures, 4 tables; accepted for publication in A&A

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Cited by in corpus (5)

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• The 3D non-LTE solar nitrogen abundance from atomic lines
• Mutual neutralisation in Li${}^{+}$+H${}^{-}$/D${}^{-}$ and Na${}^{+}$+H${}^{-}$/D${}^{-}$ collisions: Implications of experimental results for non-LTE modelling of stellar spectra
• Revisiting inelastic Cu+H collisions and the non-LTE Galactic evolution of copper
• Excitation and charge transfer in low-energy hydrogen atom collisions with neutral manganese and titanium