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Lego Figure holding a lego telescope. Photo

Henrik Hartman

Researcher (Leave of Absence)

Lego Figure holding a lego telescope. Photo

The FERRUM project: Experimental lifetimes and transition probabilities from highly excited even 4d levels in Fe II


  • Henrik Hartman
  • Hampus Nilsson
  • Lars Engström
  • Hans Lundberg

Summary, in English

We report lifetime measurements of the 6 levels in the 3d(6)(5D)4d e(6)G term in Fe II at an energy of 10.4 eV, and f-values for 14 transitions from the investigated levels. The lifetimes were measured using time-resolved laser-induced fluorescence on ions in a laser-produced plasma. The high excitation energy, and the fact that the levels have the same parity as the the low-lying states directly populated in the plasma, necessitated the use of a two-photon excitation scheme. The probability for this process is greatly enhanced by the presence of the 3d(6)(D-5)4p z(6)F levels at roughly half the energy difference. The f-values are obtained by combining the experimental lifetimes with branching fractions derived using relative intensities from a hollow cathode discharge lamp recorded with a Fourier transform spectrometer. The data is important for benchmarking atomic calculations of astrophysically important quantities and useful for spectroscopy of hot stars.


  • Lund Observatory - Has been reorganised
  • Atomic Physics

Publishing year





Astronomy & Astrophysics



Document type

Journal article


EDP Sciences


  • Atom and Molecular Physics and Optics


  • atomic data
  • methods: laboratory: atomic
  • techniques: spectroscopic




  • ISSN: 0004-6361