Measurement of radiative lifetimes of low-lying excited states in sodiumlike, fluorinelike, and oxygenlike iron

We have used the beam-foil technique to study the spectra of Fe XVI to Fe XX ions in the far vacuum ultraviolet range and to measure the mean lives of the upper levels of the 3s-3p and 3p-3d transitions in sodiumlike Fe XVI, the 2s²2p⁵²P3/2ᵒ-2s2p⁶²S1/2 resonance transition in F-like Fe XVIII, and the 2s²2p⁴³P₂-2s2p⁵³P₂ᵒ resonance transition in O-like Fe XIX. Deduced oscillator strengths are in good agreement with relativistic calculations. Tentative identifications are proposed for neonlike Fe XVII.