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- Engström, Lars, et al.
(författare)
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The FERRUM project : Experimental transition probabilities from highly excited even 5s levels in Cr ii
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 570
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Tidskriftsartikel (refereegranskat)abstract
- We report lifetime measurements of the five levels in the 3d4(a5D)5s e6D term in Cr ii at an energy around 83 000 cm-1, and log(g f ) values for 38 transitions from the investigated levels. The lifetimes are obtained using time-resolved, laser-induced fluorescence on ions from a laser-produced plasma. Since the levels have the same parity as the low-lying states directly populated in the plasma, we used a two-photon excitation scheme. This process is greatly facilitated by the presence of the 3d4(a5D)4p z6F levels at roughly half the energy di erence. The f -values are obtained by combining the experimental lifetimes with branching fractions derived using relative intensities from a hollow cathode lamp recorded with a Fourier transform spectrometer.
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