Inner-shell photoexcitation in an open-shell atom: The Cl 2p -\u3e ns,md spectrum as a case study

The 2p-- \u3e ns,md excitation spectrum has been measured and calculated for the open-shell C1 atom. A satisfactory accord between experiment and theory was found. Rydberg series cannot be discerned for transitions leading to a 2p, 3p, n iota open-shell configuration. The 4s,3d manifolds are dominant, and the 2p-3p coupling is seen to be much stronger than the 3p-n iota coupling. Very narrow widths, 16 to 22 meV, for the 4s and 3d lines an observed. By contrast, only broad structures appear in the region of the highest excitations