An experimental and theoretical characterization of the electronic structure of doubly ionised disulfur

Abstract

Using time-of-flight multiple electron and ion coincidence techniques in combination with a helium gas discharge lamp and synchrotron radiation, the double ionisation spectrum of disulfur (S_2) and the subsequent fragmentation dynamics of its dication are investigated. The S_2 sample was produced by heating mercury sulfide (HgS), whose vapour at a suitably chosen temperature consists primarily of two constituents: S_2 and atomic Hg. A multi-particle-coincidence technique is thus particularly useful for retrieving spectra of S_2 from ionisation of the mixed vapour. The results obtained are compared with detailed calculations of the electronic structure and potential energy curves of S_2^{2+} which are also presented. These computations are carried out using configuration interaction methodology. The experimental results are interpreted with and strongly supported by the computational results.