Observations of n = 3 → n′ = 4 transitions in the Mg i and Si i sequences for elements chromium through zinc

Abstract

Extreme ultraviolet spectra of 3p2-3p4d and 3p3d-3p4f transition arrays in twelve- and fourteen-electron ions, which differ by only a closed 3s2 subshell, are investigated in more detail than hitherto obtained for the elements chromium through zinc. The spectra were obtained with a two-meter vacuum spectrograph using a high-voltage spark source. Single- and multi-configuration calculations were carried out to compare predictions obtained for different model assumptions, and for the two different sequences.