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Calcite-water interface reactions are of major importance in various environmental settings as well as in industrial applications. Here we present resonant interface diffraction results on the calcite(104)-aqueous solution interface{,} measured in solutions containing either 10 mmol L-1 RbCl or 0.5 mmol L-1 Se(vi). Results indicate that Rb+ ions enter the surface adsorbed water layers and adsorb at the calcite(104)-water interface in an inner-sphere fashion. A detailed analysis based on specular and off-specular resonant interface diffraction data reveals three distinct Rb+ adsorption species: one 1.2 A above the surface{,} the second associated with surface adsorbed water molecules 3.2 A above the surface{,} and the third adsorbed in an outer-sphere fashion 5.6 A above the surface. A peak in resonant amplitude between L = 1.5 and L = 3.0 is interpreted as signal from a layered electrolyte structure. The presence of a layered electrolyte structure seems to be confirmed by data measured in the presence of Se(vi).

We describe the synthesis of cerium, thorium and uranium oxide nanoparticles embedded in a mesoporous matrix as template in a kind of nanocasting technique. The solid matrix is used as a template to obtain and stabilize the actinide oxide nanoparticles. We apply high resolution transmission electron microscopy (HR-TEM) to show evidence of metal oxide incorporation into the matrix pores and analyze their structure. Measured interplanar distances and calculated lattice parameters for synthesized nanosized CeO2−x and ThO2 samples differ from their bulk crystalline counterparts. We obtain with our synthesis CeO2−x particles containing both Ce4+ and larger sized Ce3+. The lattice parameter for these ceria nanoparticles is found to be larger than the bulk value due to the presence of Ce3+ with its larger ionic radius. The presence of Ce3+ was established by means of high resolution X-ray emission spectroscopy (HRXES), applied to the investigation of nanoparticles for the first time. The ThO2 nanoparticles exhibit a decrease in interplanar distances, as one might generally expected for these nanoclusters. However, the lattice distance decrease for our particles is remarkable, up to 5%, indicating that contact with the surrounding silica matrix may exert a bond distance shortening effect such as through significant external pressure on the particle surface.

Reference spectra of well characterized samples are crucial for the analysis of x-ray absorption spectra (XAS). In order to avoid that experimentalists have to repeat XAS measurements of standard actinide compounds/species, thereby making more efficient use of costly radionculides, sample preparation, beamtime, radioprotection measures, transport, administration, etc., we are in the process of establishing a public database of actinide XAS reference spectra. The spectra are retrieved from the large data inventory of the three current European radionuclide beamlines, the Rossendorf Beamline at ESRF (France), the INE beamline at ANKA (Germany), and the micro-XAS beamline at SLS (Switzerland), but will also include data from other beamlines. This effort is supported by the European Commission through the ACTINET-I3 project. An overview on data base structure, criteria for data entry and use, as well as on the current status of data will be given.

The working group “Analytical Methods using Radionuclides and High-performance Sources” (in German: Analytik mit Radionukliden und Hochleistungsstrahlenquellen, ARH) of the German Chemical Society (in German: Gesellschaft Deutscher Chemiker, GDCh) is supported by the GDCh Groups Nuclear Chemistry, Analytical Chemistry, Macromolecular Chemistry, Solid State Chemistry and Materials Research and the Wöhler Association of Inorganic Chemistry. The ARH working group aims at promoting and supporting the use of radionuclides especially for quality assurance of other analytical methods and analytical methods using large research facilities including synchrotron, neutron and ion sources. The main specific objectives and tasks of ARH are: • Dissemination of scientific methodology and experience, knowledge transfer • Coordination and promotion of analytical work with radioactive substances • Utilization of radio-analytical methods by improving access to radiation facilities, associated instrumentation and isotope laboratories • Facilitate access to high-performance radiation sources • Contribution to quality assurance and validation in analytical methods • Establishment and reinforcing contacts with other scientific associations • Organization of scientific conferences and meetings The ARH is continually growing, with the largest relative growth of student members over the past six years. You can become a member of the ARH working group if you belong to one of the supporting GDCh Groups listed above, are an interested company, which is a corporate GDCh member, or are an associated GDCh member in Germany or abroad (note, this is with limited member rights). Members of the German Physical Society (DPG) are also welcome to join the ARH working group with guest status. More information can be found at our website www.gdch.de/arh.

Nonresonant inelastic x-ray scattering (NIXS) experiments have been performed to probe the 5d-5f electronic transitions at the uranium O 4,5 absorption edges in several systems characterized by either a localized or itinerant character of the U5f electrons, namely, UO2, USe, US, and elemental uranium in the α form. For small values of the scattering vector q, the spectra are dominated by dipole-allowed transitions encapsulated within the ill-defined giant resonance, whereas for higher values of q the multipolar transitions of rank k=3 and 5 give rise to strong and well-defined multiplet peaks in the pre-edge region. The origin of the observed nondipole multiplet structures is explained on the basis of many-electron atomic spectral calculations. The results obtained demonstrate the high potential of NIXS as a bulk-sensitive technique for the characterization of the electronic properties of actinide materials. The different U compounds show strong variations in the O5 structure that can be correlated with the ground-state properties of the materials. © 2010 The American Physical Society.

Der Arbeitskreis „Analytik mit Radionukliden und Hochleistungsstrahlenquellen“ (ARH) wird gemeinsam von den GDCh-Fachgruppen „Nuklearchemie”, „Analytische Chemie”, „Makromolekulare Chemie“, „Festkörperchemie und Materialforschung“ und der „Wöhler-Vereinigung für Anorganische Chemie“ getragen. Der ARH Vorstand setzt sich aus Synchrotron-, Neutronen- und Ionen-Experten zusammen und steht hiermit in direktem Bezug zum SNI2010. Der Arbeitskreis setzt sich die Förderung und den Einsatz von Radionukliden zur Qualitätssicherung von Analysenverfahren und die Analytik mit Großgeräten zum Ziel. Zurzeit strebt der ARH-Vorstand insbesondere eine Vertiefung von Kontakten zu anderen wissenschaftlichen Vereinigungen wie dem „Komitee für Synchrotronstrahlung“ (KFS) und dem Komitee Forschung mit nuklearen Sonden und Ionenstrahlen (KFSI) an. Ein weiterer Schwerpunkt ist die (Fort-)Bildung sowie der Wissenstransfer und der Erfahrungsaustausch in Form von wissenschaftlichen Tagungen und Seminaren. Zum Beispiel finden das 23. SAAGAS („Seminar Aktivierungsanalyse und Gammaspektroskopie“) im September 2009 und der Workshop „Ionenstrahlphysik“ im März 2010 in Dresden statt. In dieser Posterpräsentation werden der Arbeitskreis ARH, seine Arbeitsschwerpunkte und Ziele sowie zukünftige Aktivitäten dargestellt.

The first coordination sphere of the uranyl cation in room temperature ionic liquids "IL's" results from the competition between its initially bound counterions, the IL anions, and other anions (e.g. present as impurities, or added to the solution). We present a joined spectroscopic (UV-visible and EXAFS) – simulation study of the coordination of uranyl initially introduced either as its UO2X2 salts (X- = nitrate NO3-, triflate Tf-, perchlorate ClO4-) or as UO2(SO4) in a series of imidazolium – based ILs (A- = PF6-, Tf2N-, BF4-), as well as in the Me3NBuTf2N IL. The solubility and dissociation of the uranyl salts are found to depend on the nature of X- and A-. For instance, in the BumimTf2N liquid, UO2(SO4) is insoluble, the UO2(NO3)2 salt dissolves without dissociation, while the UO2(Tf)2 and UO2(ClO4)2 salts are soluble, likely in their complexed and dissociated form, respectively.

The complexation of Cm(III) and Eu(III) with n-C3H7-BTP in non-aqueous organic solution was studied with extended X-ray absorption spectroscopy. Bond lengths are the same in both complexes. Quantum chemical calculations performed at different levels support this finding. On the other hand, the Cm•(n-C3H7-BTP)3 complex is formed at much lower metal-to-ligand concentration ratio than the Eu•(n-C3H7-BTP)3 complex, as shown by time-resolved laser-induced fluorescence spectroscopy. This is in good agreement with n-C3H7-BTP’s high selectivity for trivalent actinides over lanthanides in liquid-liquid extraction.