Issue |
A&A
Volume 437, Number 1, July I 2005
|
|
---|---|---|
Page(s) | 345 - 354 | |
Section | Atomic, molecular, and nuclear data | |
DOI | https://doi.org/10.1051/0004-6361:20041885 | |
Published online | 10 June 2005 |
Atomic data from the Iron Project
LIX. New radiative transition probabilities for Fe IV including fine structure
Department of Astronomy, The Ohio State University, Columbus, OH 43210, USA e-mail: nahar@astronomy.ohio-state.edu
Received:
23
August
2004
Accepted:
26
February
2005
We present new calculations for transition probabilities
of Fe IV, with much more extensive datasets than heretofore available,
for a variety of astrophysical applications. The large-scale close
coupling R-matrix calculations yield 1,798 LS bound states with and
, and corresponding 138 121 dipole allowed
transitions in the form of oscillator strengths f, line strengths
S, and A-coeffficients. This represents the largest R-matrix dataset
in LS coupling for any ion under either the Opacity Project or the
Iron Project. Through algebraic transformation of the LS multiplets,
a total of 712 120 dipole allowed fine structure transitions for Fe
IV are obtained. Observed transition energies, whenever available,
are used together with the energy independent line strengths to derive
the f- and the A-values for improved accuray; the adopted algorithm
used calculated energies for the remainder. Present results show
significantly better accuracy for the important low-lying states than
previous calculations. Monochromatic and mean opacities for Fe IV are
computed and compared with those obtained using the Opacity Project
data. We find differences which could have important consequences for
several astrophysical applications involving low ionization stages of iron.
Key words: atomic processes / line: formation / radiation mechanisms: thermal / radiative transfer / ISM: HII regions / radio lines: galaxies
© ESO, 2005
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