Researchers of this group investigate the surface properties of solid states by means of photoelectron spectroscopy. Two photoelectron spectrometers are available for this purpose: ADES 400 (VG Scientific, UK) and AXIS Supra (Kratos Analytical, UK. The spectrometer ADES 400 purchased in 1980 is mostly used for studying single crystals. The spectrometer AXIS Supra allows programmable and mostly automatic measurements. The extraordinary sensitivity of a detector, high energy resolution, monochromatized x-ray source and compensation of surface charging result in photoelectron spectra of high quality.