XPS study of the oxidized pyrite surface

The core level spectra of pristine and oxidized mineral pyrite FeS2 surfaces were studied using synchrotron excited photoelectron spectroscopy. In addition to the bulk feature, three surface core level shifted components were identified in the sulphur 2p spectra. After measuring the spectra of the clean pristine surface, the sample was oxidized for 12 h in O2 atmosphere. The effect of this treatment of the specimen, besides causing weakening in the signal intensities, was observed as changes in the surface core level shifts (SCLS). The surface components of the oxidized pyrite spectra were shifted towards higher binding energies compared to those of the pristine sample. The reason for this phenomenon is briefly discussed.