The FERRUM project: laboratory-measured transition probabilities for Cr II
Abstract
Aims: We measure transition probabilities for Cr II transitions from the z 4H_J, z 2D_J, y 4F_J, and y 4G_J levels in the energy range 63 000 to 68 000 cm-1.
Methods: Radiative lifetimes were measured using time-resolved laser-induced fluorescence from a laser-produced plasma. In addition, branching fractions were determined from intensity-calibrated spectra recorded with a UV Fourier transform spectrometer. The branching fractions and radiative lifetimes were combined to yield accurate transition probabilities and oscillator strengths.
Results: We present laboratory measured transition probabilities for 145 Cr II lines and radiative lifetimes for 14 Cr II levels. The laboratory-measured transition probabilities are compared to the values from semi-empirical calculations and laboratory measurements in the literature.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- February 2010
- DOI:
- arXiv:
- arXiv:1001.2139
- Bibcode:
- 2010A&A...511A..68G
- Keywords:
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- atomic data;
- line: identification;
- methods: laboratory;
- techniques: spectroscopic;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 13 pages. Accepted for publication in A&