Non-coherent scattering in subordinate lines: II. Collisional redistribution

P. Heinzel, I. Hubený

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


A suitable form of the laboratory-frame redistribution function for the resonance scattering in subordinate lines, allowing for the radiative as well as collisional broadening of both atomic levels involved, is derived. Starting from the quantum-mechanical atomic-frame redistribution of Omont et al., we rewrite it in the form of a linear combination of two redistribution functions rV and rIII, discussed in the preceding paper. This form, which is a direct generalization of that for resonance lines, permits both a simple physical interpretation and an effective numerical evaluation of the corresponding laboratory-frame redistribution. The case of spatial degeneracy is also discussed. Considerable attention is drawn to a discussion of the basic physical assumptions used, namely, the impact approximation and the Maxwellian velocity-distribution for the lower state atoms. It is shown that both of these assumptions are reasonably well satisfied for a variety of cases of astrophysical interest. Finally, in the Appendix we try to clarify the question of the normalization of the redistribution functions (with respect to inelastic collisions), as well as the question of practical equivalence between the astrophysical applications of the results of Omont et al. and those obtained by Yelnik and Voslamber.

Original languageEnglish (US)
Pages (from-to)1-14
Number of pages14
JournalJournal of Quantitative Spectroscopy and Radiative Transfer
Issue number1
StatePublished - Jan 1982
Externally publishedYes

ASJC Scopus subject areas

  • Radiation
  • Atomic and Molecular Physics, and Optics
  • Spectroscopy


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