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A system for treating XPS samples containing easily volatile and reactive adsorption layers is described. Desorg tion and reactions with atmospheric gases prior to the measurement are avoided by repeated exposure of the sample to an inert atmosphere at room temperature followed by cooling to liquid nitrogen temperature and sub sequent evacuation to spectrometer vacuum.The method has been applied to pyrite (FeS,) samples treated in aqueous potassium ethyl xanthate (dithiocarbonate) solutions. In agreement with previous indirect predictions of infrared and electrochemical measurements, the results confirm, under certain conditions of sample preparation, the presence of dixanthogen adsorp tion layers on FeS, that have not been found previously on XPS measurements.Application of the method to surface studies related to sulphide flotation is especially important because of the volatility of several species possibly existing in the collector adsorption layer. Other potential applications are corrosion and catalysis studies.

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Spinel AgIn 5 S 8 and CuIn 5 S 8 materials are perspective for application in optoelectronic semiconductor devices. For the first time, thin films of these compounds were grown and investigated. The films were deposited by a sequential process on Mo-coated soda lime glass. This process consists of sulphur vapour sulphurization of a metallic alloy precursor. We found that a good adhesion to the substrate (Mo-coated glass) could be achieved by introduction of a Ti layer between the substrate and the spinel layer. The spinel layers have been investigated by XRD and XPS methods. Moderate roughness of the films and a crystallite size of about 200 -400 nm were observed in the AFM images.

The electronic properties of a series of colossal magnetoresistance (CMR) compounds, namely LaMnO3, La(1-x)Ba(x)(MnO3 (0.2 < or = x < or = 0.55), La(0.76)Ba(0.24)Mn(0.84)Co(0.16)O3, and La(0.76)Ba(0.24)Mn(0.78)Ni(0.22)O3, have been investigated in a detailed spectroscopic study. A combination of X-ray photoelectron spectroscopy (XPS), X-ray emission spectroscopy (XES), X-ray absorption spectroscopy (XAS), and resonant inelastic X-ray scattering (RIXS) was used to reveal a detailed picture of the electronic structure in the presence of Ba, Co, and Ni doping in different concentrations. The results are compared with available theory. The valence band of La(1-x)()Ba(x)MnO3 (0 < or = x < or = 0.55) is dominated by La 5p, Mn 3d, and O 2p states, and strong hybridization between Mn 3d and O 2p states is present over the whole range of Ba concentrations. Co-doping at the Mn site leads to an increased occupancy of the e(g) states near the Fermi energy and an increase in the XPS valence band intensity between 0.5 and 5 eV, whereas the Ni-doped sample shows a lower density of occupied states near the Fermi energy. The Ni d states are located in a band spanning the energy range of 1.5-5 eV. XAS spectra indicate that the hole doping leads to mixed Mn 3d-O 2p states. Furthermore, RIXS at the Mn L edge has been used to probe d-d transitions and charge-transfer excitations in La(1-x)Ba(x)MnO3.