The crystal monochromator beamline KMC-1 at a BESSY II bending magnet covers the energy range from soft (1.7 keV) to hard x-rays (12 keV) employing the (n,-n) double crystal arrangement with constant beam offset. The monochromator is equipped with three sets of crystals, InSb, Si (111), and Si (422) which are exchangeable in situ within a few minutes. Beamline and monochromator have been optimized for high flux and high resolution. This could be achieved by (1) a windowless setup under ultrahigh-vacuum conditions up to the experiment, (2) by the use of only three optical elements to minimize reflection losses, (3) by collecting an unusually large horizontal radiation fan (6 mrad) with the toroidal premirror, and (4) the optimization of the crystal optics to the soft x-ray range necessitating quasibackscattering crystal geometry (theta(Bragg,max)=82 degrees) delivering crystal limited resolution. The multipurpose beamline is in use for a variety of user facilities such as extended x-ray absorption fine structure, ((Bio-)EXAFS) near-edge x-ray absorption fine structure (NEXAFS), absorption and fluorescence spectroscopy. Due to the windowless UHV setup the k edges of the technologically and biologically important elements such as Si, P, and S are accessible. In addition to these experiments this beamline is now extensively used for photoelectron spectroscopy at high kinetic energies. Photon flux in the 10(11)-10(12) photons/s range and beamline resolving powers of more than E/DeltaE approximately 100.000 have been measured at selected energies employing Si (nnn) high order radiation in quasibackscattering geometry, thus photoelectron spectroscopy with a total instrumental resolution of about 150 meV is possible. This article describes the design features of the beamline and reports some experimental results in the above mentioned fields.

Extended x-ray absorption fine-structure studies have been performed at the Zn K and Cd K edges for a series of solid solutions of wurtzite Zn 1−x Cd x S samples with x = 0.0, 0.1, 0.25, 0.5, 0.75, and 1.0, where the lattice parameter as a function of x evolves according to the well-known Vegard's law. In conjunction with extensive, large-scale first-principles electronic structure calculations with full geometry optimizations, these results establish that the percentage variation in the nearest-neighbor bond distances are lower by nearly an order of magnitude compared to what would be expected on the basis of lattice parameter variation, seriously undermining the chemical pressure concept. With experimental results that allow us to probe up to the third coordination shell distances, we provide a direct description of how the local structure, apparently inconsistent with the global structure, evolves very rapidly with interatomic distances to become consistent with it. We show that the basic features of this structural evolution with the composition can be visualized with nearly invariant Zn-S 4 and Cd-S 4 tetrahedral units retaining their structural integrity, while the tilts between these tetrahedral building blocks change with composition to conform to the changing lattice parameters according to the Vegard's law within a relatively short length scale. These results underline the limits of applicability of the chemical pressure concept that has been a favored tool of experimentalists to control physical properties of a large variety of condensed matter systems.

Photoemission data taken with hard x-ray radiation on cleaved single crystals of the barium parent compound of the MFe 2 As 2 pnictide high-temperature superconductor family are presented. Making use of the increased bulk sensitivity upon hard x-ray excitation, and comparing the results to data taken at conventional vacuum ultraviolet photoemission excitation energies, it is shown that the BaFe 2 As 2 cleavage surface provides an electrostatic environment that is slightly different to the bulk, most likely in the form of a modified Madelung potential. However, as the data argue against a different surface doping level, and the surface-related features in the spectra are by no means as dominating as seen in systems such as YBa 2 Cu 3 O x , we can conclude that the itinerant, near-E F electronic states are almost unaffected by the existence of the cleavage surface. Furthermore, exploiting the strong changes in photoionization cross section between the Fe and As states across the wide photon energy range employed, it is shown that the degree of energetic overlap between the iron 3d and arsenic 4p valence bands is particularly small at the Fermi level, which can only mean a very low degree of hybridization between the Fe 3d and As 4p states near and at E F . Consequently, this means that the itinerancy of the charge carriers in this group of materials involves mainly the Fe 3d-Fe 3d overlap integrals with at best a minor role for the Fe 3d-As 4p hopping parameters and that the states which support superconductivity upon doping are essentially of Fe 3d character.

The Auger electron decay parameters u2 for krypton M4,,-N2,,N2,, transitions induced by photon impact are determined experimentally and compared with theoretical predictions. Apart from the M4,5-N2,3N2,3 ' S o transitions, poor agreement is found, which might be attributed to the angular momentum coupling scheme used in the theoretical approach.Inner-shell ionisation followed by an Auger transition is described normally as a two-step process. As a consequence, the angular distribution parameter, p k , of the Auger electrons emitted can be factorised into two constituents: the alignment tensor component, d k o (later referred to as the alignment parameter), and the Auger decay parameter, a,. d k o describes the differences in the population probabilities of the magnetic sublevels of the intermediate inner-shell hole state while the decay parameter, f f k , depends on the contributing Auger amplitudes Kabachnik 1977, Aberg andHowat 1982). If the decaying ion state is produced by photoionisation, dipole selection rules restrict the possible k values to k = 2 (and trivially k = 0 ) , and the anisotropic angular distribution of Auger electrons is given by: I ( @ ) = Io( 1 + P,P,(COS 0))(1) with p2= OP2,,a2 and 0 the angle between the Auger electron and the electric vector of the linearly polarised incident radiation.Here, we will concentrate on the P2 values caused by photoionisation. Contrary to the angular distribution parameter, P 2 , of photoelectrons, the Auger electron angular distribution parameter, p2, is usually small and restricted within a much more limited range than between -1 and 2. This makes the experimental determination of p 2 and

HfO(2) thin films of different thicknesses and deposited by two methods (ALD and MOCVD) were studied. The microstructure of films was characterized by reflection spectroscopy, x-ray diffraction (XRD), and soft x-ray reflectometry. It was established that the HfO(2) film microstructure is closely dependent on film thickness. The 5 nm thick film synthesized by ALD shows an amorphous phase while the film prepared by MOCVD was inhomogeneous in depth and showed signs of crystalline structure. First results on the reconstruction of the depth distribution of chemical elements based on the analysis of reflectivity curves are discussed.