H, He-like recombination spectra – IV. Clarification and refinement of methodology for l-changing collisions

N R Badnell, F Guzmán, S Brodie, R J R Williams, P A M van Hoof, M Chatzikos, G J Ferland

Research output: Contribution to journalArticlepeer-review

Abstract

Precise spectral diagnostic modelling of H i and He ii recombination spectra can constrain theoretical models that describe many astrophysical environments. Simple analytic expressions are of interest for collisional l-changing rate coefficients that are used by large-scale population modelling codes. We review, clarify, and improve upon the modified Pengelly & Seaton formulae of Guzmán et al. We show that the recent poor results for it shown by Vrinceanu et al. are due to their misinterpretation of its usage. We also detail efficient numerical algorithms which should enable the full quantum mechanical expression for such rate coefficients to be used much more routinely by modelling codes. We illustrate with some collisional-radiative population modelling for hydrogen.
Original languageEnglish
Pages (from-to)2922-2929
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume507
Issue number2
Early online date14 Aug 2021
DOIs
Publication statusPublished - 31 Oct 2021

Keywords

  • Space and Planetary Science
  • Astronomy and Astrophysics

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