We present extensive calculations of radiative transition rates and electron impact collision strengths for Fe ii. The data sets involve 52 levels from the 3d7, 3d64s, and 3d54s2 configurations. Computations of A-values are carried out with a combination of state-of-the-art multiconfiguration approaches, namely the relativistic Hartree–Fock, Thomas–Fermi–Dirac potential, and Dirac–Fock methods, while the R-matrix plus intermediate coupling frame transformation, Breit–Pauli R-matrix, and Dirac R-matrix packages are used to obtain collision strengths. We examine the advantages and shortcomings of each of these methods, and estimate rate uncertainties from the resulting data dispersion. We proceed to construct excitation balance spectral models, and compare the predictions from each data set with observed spectra from various astronomical objects. We are thus able to establish benchmarks in the spectral modeling of [Fe ɪɪ] emission in the IR and optical regions as well as in the UV Fe ɪɪ absorption spectra. Finally, we provide diagnostic line ratios and line emissivities for emission spectroscopy as well as column densities for absorption spectroscopy. All atomic data and models are available online and through the AtomPy atomic data curation environment.
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We acknowledge support from the NASA Astronomy and Physics Research and Analysis Program (Award NNX09AB99G) and the Space Telescope Science Institute (Project GO-11745). V.F. is currently a postdoctoral researcher of the Return Grant Program of the Belgian Scientific Policy (BELSPO). P.Q. is Research Director of the Belgian National Fund for Scientific Research F.R.S.-FNRS.
Bautista, Manuel A.; Fivet, Vanessa; Ballance, Connor; Quinet, Pascal; Ferland, Gary J.; Mendoza, Claudio; and Kallman, Timothy R., "Atomic Data and Spectral Model for Fe ɪɪ" (2015). Physics and Astronomy Faculty Publications. 365.