3p⁶–3p⁵3d Transitions of Fe IX and Ni XI in the Solar Spectrum

Abstract

USING rocket spectroscopy, Hinteregger et al.¹ obtained interesting new solar lines, the majority of which could not be classified up to now. Among these lines, two strong lines at 171.1 Å and at 148.5 Å have been seen. We have been able, using the technique of differentiation between different degrees of ionization^2,3, to classify these two lines as the 3p^{6 1}S₀ – 3p⁵3d ¹P₁ transition of Fe IX and Ni XI. This line was found to be very prominent in the isoelectronic sequence of A I (Table 1). The foregoing classification is based on the assumption of LS coupling.