The H₂S⁺radical ion

Abstract

The emission spectrum between 4000 and 5000 Å obtained by Horani, Leach and Rostas by controlled energy electron excitation of H2S is shown to belong to H2S+. The decrease and subsequent increase of the bending vibrational intervals in the à 2 A 1 state of H2S+ and D2S+ indicates a barrier to linearity of approximately 4600 cm-1. A preliminary rotational analysis of the spectrum leads to the following molecular parameters for the ground state: r 0″ = 1·358 Å, valence angle 92° 54′. A detailed comparison of the optical and photoelectron spectra has been made and selection rules for the photoelectron spectra are presented. It is shown that in order to understand the vibronic patterns of both types of spectra it is necessary to consider in detail Renner-Teller vibronic interaction. A barrier to linearity in the 2 A 1 state of H2S+ alone is insufficient to account for the interesting change in the spectrum of the 2 A 1-1 A 1 transition at energies corresponding to the potential maximum.