New measurements of spontaneous transition probabilities for beryllium-like ions

Complementary investigations using the MCDF and RQDO methods

“…The spectra of Be‐like ions are frequently observed in astronomical and laboratory plasmas 26–29. Several transitions in FeXXIII have also been identified in solar flare spectra, iron being the most abundant heavy element in the solar corona 30, 31.…”

Calculations of wavelengths and transition probabilities in the singlet and triplet spectra of N IV

“…There have, in fact, been several calculations for this oscillator strength [20-241 and they all lie in the range 0.576 to 0.666. An error in the lifetime of the common upper 2s3p 'Po level employed by Lang et al [7] cannot explain both discrepancies since, in one case, the model-potential A value is a factor of 5 too large and, in the other case, it is a factor of 5 too small. We also remark that our 2s3p 'Po lifetime differs by less than 10% from the experimental values [25].…”

“…Lang et al [7] have recently measured a number of transition probabilities for 2-3 and 3-3 transitions in N IV. The experimental method measured branching ratios and employed known lifetimes for the common upper levels to deduce transition probabilities.…”

“…There is a paucity of transition probability data for the observed spectral lines. Lang et al [7] recently measured rates for a number of transitions between low-lying levels in beryllium-like ions, including N IV, and in several cases obtained results which are not in accord with available theoretical values.…”