Experimental oscillator strengths for the resonance lines in Na- and Mg-like iron

Abstract

In this paper we present accurate measurements of the lifetimes for the 3s3p 1P and 3p 2P levels in the Mg- and Na-like species of iron. The measurements were done using the beam-foil technique combined with the ANDC/CANDY cascade correction method. We find good agreement between theory and experiment for the 3s3p 1P lifetime in the Mg-like ion Fe XV, whereas for the 3p 2P levels in the Na-like ion, Fe XVI, the experimental value is somewhat longer than predicted by relativistic calculations. Comparisons of the experimental and theoretical oscillator strength for the resonance line, and for the lifetime of the 3p 2 1D 2 level along the Mg I isoelectronic sequence, up to Z = 28, are also presented.