Remarks:

The actual project for a Spanish Beamline at the ESRF in Grenoble is today a necessity for the Spanish XAS users. Moreover, the existence of experienced groups guarantees the competitive use of this high flux source. In particular, the combination in "branch A" of complementary techniques, i.e. two axis diffractometry and X-ray absorption spectroscopy, makes it of great interest in many problems of Science, in particular in Solid State Physics and Chemistry allowing the simultaneous or quasi- simultaneous use of diffraction and absorption detectors. It is proposed to open new possibilities with quasi-simultaneous absorption/diffraction analysis as well as to improve the station to carry out real time experiments as well as high resolution and anomalous diffraction studies. It will allow to apply the new emerging techniques as Diffraction Anomalous Fine Structure (DAFS) or X-ray Resonant Magnetic Scattering. Although this beamline is not designed for polarization dependent absorption, the activity of some Spanish groups in the related technique of XCMD to study the local magnetism in hard magnetic materials(48-50) must be underlined. As a matter of future, the use of X-ray quarter-wave plate will allow to perform these kinds of experiments.

  • Fundamentals of XAS.

    The richness of the electronic and structural information supplied by XAS is sometimes not well exploited due to the lack of an appropriate theoretical frame. EXAFS is today a well established technique and it is generally accepted that a further development is not necessary, but for a correct interpretation of the data it is necessary sometimes to take into account multiple scattering effects and many body effects as multielectron excitations. In spite of the success of the multiple scattering description of the XANES spectra that have allowed to interpret it in a unique theoretical frame and to get information on geometry (three particle correlation function) and electronic state of the absorber atom, there are still some problems associated essentially to the approximations included in the theoretical calculations, probably due to the use of the muffin tin approximation.

  • Catalysis.

    X-ray Absorption spectroscopy is a technique particularly appropriate for the study of homogeneous and heterogeneous catalysts. The selectivity of the technique to determine the electronic and geometric structure around the active atom is particularly useful to determine the mechanisms responsible for the catalytic activity.

  • Nanostructured materials.

    Nanostructured materials and nanocomposites, characterized by an ultrafine grain size (50<nm), have attracted interest in recent years by virtue of their unusual mechanical, electrical, optical and magnetic properties The UPV group has studied these kinds of materials due to their magnetic properties.

  • Thin films and coatings.

    The synthesis and characterization of thin films and coatings is of fundamental interest due to the high number of technological applications. Coatings are used as protection against corrosion or erosion, as hard coatings for cutting tools, in optical applications, as sensors, dielectric or ferroelectric layers, etc.

  • Highly diluted species.

    The determination of the local structure of dopants in single crystals, glasses, and semiconductors.

  • Heterostructures and Superlattices.

    The study of semiconductor and metallic superlattices and heterostructures has a growing interest because the artificial modulation at atomic level shows very interesting electronic, optical, magnetic and mechanical properties.

  • Inorganic materials.

    This topic includes a wide spectra of materials that ranges from solid state materials, to solutions or liquid crystals. In general the properties of these materials come from the bulk and they can be amorphous, crystalline, ceramics, glasses etc.

  • Others:  Intermetallic alloys (crystalline and amorphous), Layered structures.