Far-ultraviolet solution spectroscopy of hydrosulphide ion

The far-ultraviolet spectra of the hydrosulphide ion in a range of red- and blue-shifting solvents shows a set of four absorption bands of differing character. The lowest energy pair, A and B, are similar to those observed for the halide ions and have high solvent sensitivities. The higher energy, higher intensity D and E bands are also similar to those found at high energies for the halides. The solvent sensitivity for the A band of HS–, relative to that for the solvated electron, is 0.85.Dissection of the energy diagram in terms of ionisation potential and ionic radius shows that the adsorption spectrum of hydrosulphide is very similar to that for bromide. On the other hand, the solvent sensitivity is close to that for chloride whilst band asymmetry parameter, ρ, and band-widths, ν½, are considerably greater than those for the halides. It is concluded that the unique character of an ion contributes to some change-transfer-to-solvent (c.t.t.s.) properties and not to others.