Abstract. Fe II radiative lifetimes were measured applying the time-resolved nonlinear laser-induced fluoresence technique. We investigated 21 levels of up to 47 000 cm −1 . The uncertainties are typically 2−3%. The lifetimes provide an improved absolute scale to our branching fractions which were measured with a Fourier transform spectrometer and a high-resolution grating spectrometer and which have been published earlier. We report absolute transition probabilities of 140 Fe II lines in the wavelength range 220-780 nm. The overall uncertainties are estimated to be 6% for the strong and up to 26% for the weak transitions. The results are compared with recent experimental data from the literature. Our large set of accurate data can be used for a reliability check of theoretical data calculated for iron abundances in astrophysical plasmas.

Abstract.We report on measurements of radiative lifetimes in singly ionized iron of six 3d 6 4p levels between 61 512 and 64 041 cm −1 , using time-resolved laser-induced fluorescence. Absolute oscillator strengths of 18 Fe II lines in the wavelength range from 2350 to 2800 Å have been obtained by measuring branching fractions for the lines from two Fe II levels with a Fouriertransform spectrometer. The uncertainty in the lifetimes is between 8% and 13%, whereas the uncertainty of the f -values varies between 9% and 19%. A comparison with several previously published values is given.

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A first small set of W III oscillator strengths has been obtained from combined lifetime and branching fraction measurements. The branching fractions in the wavelength region of 154–334 nm were measured with a Penning discharge and a Fourier transform spectrometer. Three levels have been calibrated on absolute scales with lifetimes measured with the time-resolved laser-induced fluorescence technique. The f-values derived have uncertainties of about 8% at best. A comparison with Cowan-code calculations is given since no other data are available in the literature.

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