FeII radiative transition rates

The data sets involve 52 levels from the 3d^7^, 3d^6^4s, and 3d^5^4s^2^ 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 [FeII] emission in the IR and optical regions as well as in the UV FeII absorption spectra.