Interpretation of sulphur 2p XPS spectra in sulfide minerals by means ofab initio calculations

First-principles quantum chemical calculations have been used to reproduce S 2p x-ray photoelectron spectroscopy binding energies for a number of sulphide minerals where accurate experimental data are available. Periodic calculations have been performed with the Hartree–Fock/density functional hybrid method B3LYP. Reasonable agreement between the calculated and experimentally observed S 2p3/2 binding energies was achieved for the sulphides sphalerite, wurtzite, pyrite, galena and chalcopyrite. Based on these periodic calculations simple pseudo-hydrogen-saturated cluster models were constructed that give reliable predictions for the spectra of all reference compounds, while also allowing for the treatment of more complex sulphide and polysulphide structures inaccessible to present periodic approaches.