An experimental study of the valence shell photoelectron spectrum of hydrogen sulphide Original Research Article

The complete valence shell photoelectron spectrum of hydrogen sulphide has been studied in the 10 to 25 eV binding energy region using He I, He II and synchroton radiation. Using monochromated synchroton radiation, photoelectron angular distributions and branching ratios have been determined in the 14 to 120 eV photon energy range. The results suggest that most of the prominent inner valence features should be associated with ionisation from the 4a1 molecular orbital. High resolution spectra have been obtained over a similar binding energy range using He I and He II excitation. Several narrow photoelectron bands have been observed in the region between 22.5 and 24.5 eV, and are associated with vibrational progressions belonging to two different electronic states. The He I excited spectrum has allowed a detailed analysis to be made of the vibrational and rotational fine structure exhibited in the photoelectron bands associated with ionisation from the 2b1 and the 5a1 orbitals. For the A 2A1 state, comparisons are made with the rovibronic structure predicted by Duxbury et al.