J/A+A/489/1369 Atomic Data from the Iron Project LXVI. Fe18+ (Butler+, 2008)
Atomic Data from the Iron Project LXVI.
Electron impact excitation of Fe18+.
Butler K., Badnell N.R.
<Astron. Astrophys. 489, 1369 (2008)>
=2008A&A...489.1369B 2008A&A...489.1369B
ADC_Keywords: Atomic physics
Keywords: atomic data - atomic processes - plasmas
Abstract:
Accurate electron collisional data are required for the analysis of
the Fe XIX astrophysical spectrum, in particular in the Sun. Such an
analysis can provide information on the physical characteristics of
the coronal plasma.
An extensive target is used in an R-matrix scattering calculation to
provide the necessary data for Fe18+. The use of the R-matrix
method includes the resonance contribution lacking in the distorted
wave approach and the large target improves the accuracy of the
close-coupling approximation.
The R-Matrix package described by Berrington et al. (1995) as provided
by the UK RmaX project has been used to calculate electron collisional
data among 342 levels of Fe18+. We have used the
intermediate-coupling frame-transformation (ICFT) method (Griffin et
al., 1998) to transform data obtained in a 166 term LS-coupling
calculation. Contributions from the mass and Darwin interactions have
also been included in the Hamiltonian.
Collision strengths for all transitions between the 342 levels of
Fe18+ are presented. They are tabulated over a wide range of
electron temperatures of astrophysical interest. The results are
compared with the earlier Iron Project work of Butler & Zeippen (2001,
Cat. J/A+A/372/1078) and also with that of McLaughlin et al.
(2001MNRAS.328..442M 2001MNRAS.328..442M) and Landi & Gu (2006ApJ...640.1171L 2006ApJ...640.1171L). The
agreement is reasonable for the low-lying transitions. Larger
differences are found for the more highly excited states.
The file structure is described in detail in
http://www.adas.ac.uk/man/appxa-04.pdf
A sample program to extract a single upsilon is provided.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
levels.dat 51 342 Energy levels
table4.txt 104 58665 Energy levels, transition probabilities and
collision strengths in adf04 format
getups.f 72 128 Fortran program to extract data for a single
transition
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Byte-by-byte Description of file: levels.dat
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Bytes Format Units Label Explanations
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3- 5 I3 --- Index level index
11- 35 A25 --- Level Level designation
44- 51 F8.0 cm-1 Ecalc Calculated energy
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Acknowledgements:
Keith Butler, butler(at)usm.uni-muenchen.de
(End) Patricia Vannier [CDS] 22-Jul-2008