Electron-impact Excitation of Fe i

Abstract

The Fe i spectra emitted by astrophysical sources contain information on plasma parameters such as chemical abundances and magnetic fields. However, to determine these parameters requires detailed plasma modeling, which in turn needs accurate atomic data for processes such as radiative decay and electron-impact excitation in Fe i. A lack of fine-structure resolved collision strengths for transitions in Fe i is addressed in this paper with the presentation of data obtained from a Dirac R-matrix calculation. The suitability of our choice of target description is shown, with our energies generally within 7% of literature values. Various A-values are compared with other theoretical and experimental results, and the quality of the collision strengths produced in this work demonstrated. A comparison of 300- and 1000-level close-coupling expansions is made, the latter shown to eliminate pseudoresonances in the collision strengths at electron energies between 0.5 and 1.0 Ry. Maxwell-averaged effective collision strengths are presented, and the convergence of our data is shown in the temperature range 1000–100,000 K.