Atomic data from the IRON Project LXV. Electron-impact excitation of Fe6+

Witthoeft, M.C. and Badnell, N.R. (2008) Atomic data from the IRON Project LXV. Electron-impact excitation of Fe6+. Astronomy and Astrophysics, 481 (2). pp. 543-551. ISSN 0004-6361 (http://dx.doi.org/10.1051/0004-6361:20079073)

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Abstract

We present R-matrix results for the electron-impact excitation of Fe6+. The intermediate-coupling frame transformation (ICFT) method has been used to obtain level-resolved collision strengths. We then calculate effective collision strengths assuming a Maxwellian distribution for the incident electron velocities. A large configuration interaction (CI) expansion of 1896 LS terms (4776 fine-structure levels) is used to obtain an accurate target. This is reduced to 89 close-coupling (CC) terms (189 levels) for the scattering calculation. To investigate the importance of CI, we also perform a second calculation with the same CC expansion but a smaller CI expansion. We discuss the difficulties of such a comparison and look at which transitions show the most sensitivity to the CI expansion. Our effective collision strengths are compared with a previous IRON Project report (Berrington et al. 2000, A&A, 142, 313) for transitions within the ground configuration and a recent distorted wave calculation (Zeng et al. 2005, MNRAS, 357, 440) for transitions to excited configurations. We find good agreement with the results of the previous R-matrix calculation and with the high-temperature distorted-wave results for most transitions, although there are some significant differences at lower temperatures in the latter case.

  • Item type:Article
    ID code:19746
    Dates:
    Date
    Event
    April 2008
    Published
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Strathprints Administrator
    Date deposited:27 May 2010 18:09
    Last modified:08 Apr 2024 17:37
    URI:https://strathprints.strath.ac.uk/id/eprint/19746
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