The nonresonant two-photon zero kinetic energy photoelectron spectrum from the electronic ground state of H2S

The nonresonant two-photon (1+1) ZEKE (zero kinetic energy) photoelectron spectrum from the X̃ 1A1 electronic ground state of H2S is reported. Complete rotational resolution of the X̃ 2B1 ground state of the ion was achieved for different temperatures in the jet. The ZEKE spectra show angular momentum transfer up to ΔN=2. The rotationalNKa+Kc++ ← J″Ka″Kc″ branching ratios for the low-lying rotational levels were determined. The strongest transitions are those with ΔKa=Ka+−Ka″=±1 and ΔKc=Kc+−Kc″=0 (type c transitions) but transitions with ΔKa=0 and ΔKc=±1 (type a transitions) also show a surprisingly high intensity. Changes in Ka or Kc up to ±3 are observed. The two-photon spectra are compared with those obtained via one-photon VUV photoionization by other authors.