Effective collision strengths for fine-structure forbidden transitions among the 2s22p3 levels of Ne IV

C. A. Ramsbottom*, K. L. Bell, F. P. Keenan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Effective collision strengths for electron-impact excitation of the N-like ion NeIV are calculated in the close-coupling approximation using the multichannel R-matrix method. Specific attention is given to the 10 astrophysically important fine-structure forbidden transitions among the 4So, 2Do and 2Po levels in the 2s22p3 ground-state configuration. The expansion of the total wavefunction incorporates the lowest 11 LS eigenstates of NeIV, consisting of eight n = 2 terms with configurations 2s22p3, 2s2p4 and 2p5, together with three n = 3 states of configuration 2s22p23s. We present in graphical form the effective collision strengths obtained by thermally averaging the collision strengths over a Maxwellian distribution of velocities, for all 10 fine-structure transitions, over the range of electron temperatures log T(K) = 3.6 to log T(K) = 6.1 (the range appropriate for astrophysical applications). Comparisons are made with the earlier, less sophisticated close-coupling calculation of Giles, and excellent agreement is found in the limited temperature region where a comparison is possible [log T(K) = 3.7 to log 7(K) = 4.3]. At higher temperatures the present data are the only reliable results currently available.

Original languageEnglish
Pages (from-to)233-238
Number of pages6
JournalMonthly Notices of the Royal Astronomical Society
Volume293
Issue number3
Publication statusPublished - 21 Jan 1998

Keywords

  • Atomic processes
  • Line: Formation

ASJC Scopus subject areas

  • Space and Planetary Science

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