The FERRUM project: Branching ratios and atomic transition probabilities of Fe II transitions from the 3d(aF)4p subconfiguration in the visible to VUV spectral region^*

¹ Physics Department, Blackett Laboratory, Imperial College, London SW7 2BZ, UK
² Atomic Astrophysics, Department of Astronomy, Lund University, PO Box 43, 22100 Lund, Sweden e-mail: sveneric.johansson@astro.lu.se
³ Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA e-mail: plsmith@cfa.harvard.edu

Corresponding author: J. C. Pickering, j.pickering@ic.ac.uk

Received: 23 April 2001
Accepted: 2 July 2001

Abstract

We report measurements of the relative intensities of 81 emission lines of Fe II between 160 nm and 350 nm (62 168 cm^-1 to 28 564 cm^-1) from 4 levels by high resolution Fourier transform spectrometry, using a Penning discharge lamp as light source. These relative intensities have been used to determine the line branching fractions, which have then been combined with accurate experimental radiative lifetime measurements reported recently to give absolute transition probabilities and oscillator strengths for 81 lines. The accuracy of these f-values is compared with other previous experimental measurements, and with theoretical values. The new transition probabilities will allow accurate determinations of Fe II abundances in a wide variety of astrophysical objects.