High-charge-state formation following inner-shell photodetachment from S⁻

The formation of S⁺, S²⁺, S³⁺, and S⁴⁺ is observed following inner-shell photodetachment of S⁻. The photodetachment spectra for all possible ionic products are obtained over a large region of photon energies covering both the 2p and 2s thresholds (S⁵⁺, is energetically allowed at the higher photon energies, but not observed), and are placed on an absolute scale. The 2s threshold energy is measured to be 224.6(5) eV, allowing the determination of the neutral atomic S 2s⁻¹3s²3p⁵ inner-shell excited state energy for the first time. The S⁻ 2s⁻¹3s²3p^6 2S_1∕2 state is observed as a Feshbach resonance 2.3(5) eV below the 2s threshold in the S⁺, S²⁺, and S³⁺ product channels.