Inner-shell photodetachment from the K- ion

We have measured the relative cross section for photodetachment from the K- ion for the process K- + h nu -> K+ + 2e(-) over the photon energy range 21-24.5 eV. The structures in the measured cross section are associated with correlated processes involving the detachment or excitation of a 3p core electron, processes which are often accompanied by the excitation of one or more valence electrons. The most prominent feature in the cross section is a strong resonance arising from the excitation of a 3p electron from the core and a 4s valence electron. As in previous experiments on double excitation of valence electrons, electron correlation is seen to play an important role in the dynamics of negative ions.