... Title : LASER-EXAFS: FAST EXTENDED X-RAY ABSORPTION FINE STRUCTURE SPECTROSCOPY WITH A SINGLE PULSE OF LASER ...
DTIC Science & Technology
... The Fourier transforms of the EXAFS indicate Fe-Fe interactions. ... EXAFS. yet there is a distinct Fe-Fe separation of 5.08 X. This distance is -5- ...
The oxygen binding site of hemocyanin has two copper atoms coordinated to the side chains from the polypeptide chain. Copper extended x-ray absorption fine structure (EXAFS) and absorption edges of the protein were studied. Comparison of EXAFS from three ...
National Technical Information Service (NTIS)
The experimental technics of Extended X-ray Absorption Fine Structure (EXAFS) is presented and several uses of it in atomic, molecular and bio physics are shown. The recent progresses of this technics, both theoretical and experimental, are discussed and ...
This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods ...
DOE Information Bridge
X-ray absorption spectroscopy is now being applied to the study of a wide range of surface structures. The usefulness of surface EXAFS (SEXAFS) is illustrated by reviewing measurements on the oxidation of aluminum, the absorption of Te and I on silicon an...
... x-ray absorption fine structure (EXAFS), infra-red and Raman spectroscopy, low temperature specific heat, and electron spin resonance (ESR). ...
... X-Ray absorption near edge spectroscopy (XANES); Co-K-edge EXAFS spectra were collected at the Stanford Synchrotron Radiation Laboratory ...
The past several years have witnessed the emergence of Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy from an esoteric technique to a widely available structural spectroscopic tool. Several in-depth review articles and books are available on the subject, but some aspects of theory or data reduction may be beyond the ...
Energy Citations Database
X-ray absorption fine structure (EXAFS) spectroscopy spectra were collected for three brominated persistent pollutants: 6-bromo-2,4,5-trichlorophenol (BrTriClP), pentabromophenol (PentaBrP) and 3,3',5,5'-tetrabromobisphenol A (TBBA). The substances were selected to be symmetrical (BrTriClP and TBBA) or asymmetrical (PentaBrP) with ...
PubMed
Complexes of Fe(III) with sorbitol in alkaline aqueous solutions have been investigated by EXAFS spectroscopy. The results strongly support the formation of a mononuclear complex at pH 14, a dinuclear complex at pH 13 and oligonuclear species at pH 10-13. The EXAFS spectra were recorded at 70 K in the absorption ...
NASA Astrophysics Data System (ADS)
of the DCM was calibrated relative hal-00261713,version1-8Mar2008 #12;15 to the Au K-edge of metallic gold-ray absorption near-edge spectroscopy) and EXAFS (extended x-ray absorption fine- structure) spectroscopy. Iterative transformation factor analysis of XANES and EXAFS ...
E-print Network
Neither the theory nor the interpretation of Extended X-Ray-Absorption Fine-Structure (EXAFS) spectroscopy requires assumptions of crystalline symmetry or periodicity. As a result, EXAFS is a tool applied to a wide range of scientific disciplines and to a wide variety of experimental systems. A simple enumeration ...
The main purpose of this Study Weekend was to review the contributions that the measurement and interpretation of X-ray absorption spectroscopy, particularly Extended X-ray Absorption Fine Structure (EXAPS), has made, and can make, to the improved underst...
The extended x-ray absorption fine structure (EXAFS) is the oscillation in the absorption coefficient extending a few hundred eVs on the high energy side of an x-ray absorption edge. This mode of spectroscopy has recently been realized to be a powerful tool in probing the local atomic structure ...
The results of magnetic circular x-ray dichroism (MCXD) measurements and extended x-ray absorption fine structure measurements (EXAFS) of the Fe K-edges of textured Fe(110)/Pd(111) multilayers are reported. The EXAFS results indicates that the iron in the...
The author has used the extended X-ray absorption fine structure (EXAFS) and ultra-low temperature X-ray magnetic circular dichroism (XMCD) to study the environments of the metal sites in metalloproteins. EXAFS has been used to study the Zn site in spinac...
Pt-mordenite catalysts were characterized by in situ EXAFS spectroscopy and H2 temperature-programmed desorption. The results are consistent with the presence of small intracrystalline Pt clusters. Moreover, the EXAFS data evidence Pt-Al (or Si) bonding following reduction at 450� C in H2.
Extended x-ray absorption fine structure (EXAFS) spectroscopy has been used to determine the structural environment local to iron(HI) and zircorium(IV) cations in respectively, nanoscale iron oxyhydroxide and nanoscale zirconium oxide powders. The iron ox...
The sensitivity of x-ray absorption edge spectra and extended x-ray absorption fine structure (EXAFS) to the environment of metal atoms make x-ray absorption spectroscopy a useful probe of the environment of the molybdenum in nitrogenase. It is of particular interest to investigate any ...
In this letter, we have used the extended x-ray-absorption fine-structure (EXAFS) technique to investigate the structure of Mn-rich self-organized nanocolumns grown by low temperature molecular beam epitaxy. The EXAFS analysis has shown that Mn-rich nanocolumns exhibit a complex local structure that cannot be described by a simple ...
Two heme iron enzymes, oxygenated chloroperoxidase and cytochrome P-450-CAM, have been characterized using extended X-ray absorption fine structure spectroscopy (EXAFS). The EXAFS spectra of the two compounds are identical within the spectral noise. Curve filling has lead to the conclusion that both enzymes have an ...
EXAFS (extended X-ray absorption fine structure) investigations are reported concerning the thermal expansion behaviour of silver in an extended range of temperature from 10 K to about 950 K measured in transmission mode. Both the ratio method and an EXAFS fitting procedure were applied to reveal the temperature dependence of ...
Many metal clusters in the 1-nm size range are catalytically active, and their enhanced reactivity is often attributed to their size, structure, morphology, and details of alloying. Synchrotron sources provide a wide range of opportunities for studying catalysis. Among them, extended X-ray absorption fine-structure (EXAFS) spectroscopy ...
Sputter deposited non-stoichiometric tantalum nitride films are oxidized in air between 200 and 500{degrees}C to form a passive film. The oxidized films have been studied with x-ray absorption near edge spectroscopy (XANES) and extended x-ray absorption near edge spectroscopy (EXAFS). Films ...
Fracture-EXAFS is a technique, proposed here for the first time, which combines an appropriate mechanical test with EXAFS analysis to investigate the atomic processes involved in the fracture process. Fracture-EXAFS builds upon the fracture-Auger electron spectroscopy technique, which was used to study the ...
... analysis of the kX spectrum up to 800 eV above the K edge. ... We have applied extended x-ray absorption fine structure (EXAFS) spectroscopy [1] to ...
The application of X-ray Absorption Spectroscopy (XAS) to the study of diffusion properties of oxide glasses and glass surfaces is considered. Mixed alkali silicates are discussed, as are the chemical resistance of iron-lead-phosphate glasses and the surf...
Lead phosphate glasses are characteristically prone to aqueous attack but become chemically resistant by the addition of iron. The authors have measured the K-edge EXAFS of Fe and the L(sub 3)-edge EXAFS of Pb and find the atomic environments of the two s...
Extended X-ray Absorption Fine Structure (EXAFS) experiments impose stringent requirements on a detection system, due to the need for processing ionizing events at a high rate, typically above of 10Mcps/cm2, and with a high resolution, typically better th...
X-ray absorption spectroscopy in enzymes (EXAFS) studies have been carried out on pig plasma amine oxidase containing one copper and two copper atoms. The data for the two forms are essentially identical and are consistent with the presence of four low-z ...
In this study, oriented Photosystem II (PS II) particles from spinach chloroplasts are studied with electron paramagnetic resonance (EPR) and x-ray absorption spectroscopy (XAS) to determine more details of the structure of the oxygen evolving complex (OEC). The nature of halide binding to Mn is also studied with Cl K-edge and Mn EXAFS ...
A systematic study of LaMn1?xCoxO3 perovskite series by means of X-ray absorption spectroscopy in the extended X-ray absorption fine structure (EXAFS) range of the K-absorption edge of Mn is reported. The Mn-K edge absorption measurements in the EXAFS ...
The structures of C{sub 5}H{sub 5}NiNO in a reversible photochemical reaction were studied via EXAFS, FTIR, and optical absorption spectroscopies. A photoexcited intermediate with distinctively different EXAFS, IR, and optical absorption spectra from those of the ground state molecules was ...
The structures of C[sub 5]H[sub 5]NiNO in a reversible photochemical reaction were studied via EXAFS, FTIR, and optical absorption spectroscopies. A photoexcited intermediate with distinctively different EXAFS, IR, and optical absorption spectra from those of the ground state molecules was ...
When two or more absorption edges in a material are sufficiently close in energy, Extended X-ray- Absorption Fine-Structure (EXAFS) spectroscopy is of limited utility as the usable data range above the lower energy edge is truncated by the higher energy e...
A program to investigate the x-ray absorption behavior of materials subjected to high pressures has been continued. Of particular interest has been the EXAFS (extended x-ray absorption fine structure) and XANES (x-ray absorption near edge structure). Mate...
The techniques of extended x-ray absorption fine structure (EXAFS), and x-ray absorption edge spectroscopy (XAES) are used to obtain specific structural information about the manganese coordination environment in synthetic inorganic complexes, and in biol...
Extended x-ray absorption fine structure (EXAFS) spectroscopy has been used to determine the structural environment local to iron(HI) and zircorium(IV) cations in respectively, nanoscale iron oxyhydroxide and nanoscale zirconium oxide powders. The iron oxyhydroxide powder, produced by the modified reverse micelle (MRM) technology, was ...
Extended x-ray absorption fine structure (EXAFS) spectroscopy exploits the quantum interference resulting from the scattering of a photoelectron, generated by the excitation of a core level, by the potential of the surrounding atoms. From the interference pattern it is possible to determine the distance and average distribution of the ...
The oxygen binding site of hemocyanin has two copper atoms coordinated to the side chains from the polypeptide chain. Copper extended x-ray absorption fine structure (EXAFS) and absorption edges of the protein were studied. Comparison of EXAFS from three molluscan oxyhemocyanins (Megathura crenulata, the ..cap ...
In order to understand the evolving world of environmental issues, the ability to characterize and predict the stability and bioavailability of heavy m�tal contaminants in mine waste is becoming increasingly more important. X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) ...
The nitrate complexes of Pu(IV) are studied in solutions containing nitrate at concentrations up to 13 molar (M) using absorption spectroscopy, N-15 nuclear magnetic resonance (NMR), and extended X-ray absorption fine structure (EXAFS). Four major nitrato complexes are observed and identified as Pu(NO3)(3+), ...
Arsenic is present in low concentrations in much of the Earth's crust and changes in its speciation are vital to understanding its transport and toxicity in the environment. We have used X-ray absorption spectroscopy to investigate the coordination sites of arsenic in a wide variety of samples, including soil and earthworm tissues from ...
Arsenic is present in low concentrations in much of the Earth's crust and changes in its speciation are vital to understanding its transport and toxicity in the environment. We have used X-ray absorption spectroscopy to investigate the coordination sites of arsenic in a wide variety of samples, including soil and earthworm tissues from arsenic-contaminated ...
The dinuclear iron center of the hydroxylase component of soluble methane monooxygenase (MMO) from Methylococcus capsulatus and Methylosinus trichosporiwn has been studied by X-ray absorption spectroscopy. Analysis of the Fe K-edge EXAFS revealed that the...
This report contains the following papers: characteristics of the advanced photon source and comparison with existing synchrotron facilities; x-ray absorption spectroscopy: EXAFS and XANES -- A versatile tool to study the atomic and electronic structure of materials; applications of x-ray spectroscopy and anomalous ...
Bioavailability of Cu in the soil is a function of its speciation. In this paper we investigated Cu speciation in six soils using X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and synchrotron-based micro X-ray fluorescence (mu-XRF). The XANES and EXAFS spectra in ...
The research programs reported span virtually the entire range of condensed matter studies involving the fields of solid state physics, chemistry, electrochemistry, materials science and biochemistry. Results are discussed for various groups. Topics reported include work on amorphous chalcogenide semiconductors, particularly photostructural changes, kinetics of structural changes and rapid ...
Extended X-ray absorption fine structure (EXAFS) spectroscopy has been used to investigate the metal coordination in several iron, cobalt, and cadmium metallothioneins. The samples examined comprised Fe7-, Fe3-, Co7-, Co3-, Cd4Co3-, and Cd7- metallothioneins, which are shown to coordinate only to sulphur atoms of cysteinyl residues in ...
X-ray photoelectron spectroscopy (XPS) and extended x-ray absorption fine structure (EXAFS) studies have been undertaken on sodium disilicate glasses containing varying amounts of Fe/sub 2/O/sub 3/ and UO/sub 2/. The XPS results enable one to distinguish the different bonding characteristics of iron and uranium in these glasses. A ...
The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn4Ca cluster, are described. Issues of X-ray damage especially at the metal sites in the Mn4Ca cluster are discussed. The structure of the Mn4Ca catalyst at high-resolution which has so far eluded attempts of ...
The x-ray absorption spectroscopy (XAS) had been an essential tool to gather spectroscopic information about atomic energy level structure in the early decades of this century. It has also played an important role in the discovery and systematization of rare-earth elements. The discovery of synchrotron radiation in 1952, and later the availability of ...
The author has used the extended X-ray absorption fine structure (EXAFS) and ultra-low temperature X-ray magnetic circular dichroism (XMCD) to study the environments of the metal sites in metalloproteins. EXAFS has been used to study the Zn site in spinach carbonic anhydrase. The EXAFS, in parallel with site ...
We investigate the solvation structure of aqueous potassium ions, using a combination of electronic structure calculations, statistical mechanical simulations with a derived polarizable empirical potential and experimental measurement of the Extended X-ray Absorption Fine Structure (EXAFS) spectra. The potassium K-edge (at 3608 eV) ...
The acidic character of the hydration water in NbOPO{sub 4} {center_dot} 2H{sub 2}O permits the exchange of protons for Li{sup +} ions. The lithium phase annealed at 773 K presents a slightly distorted lattice with respect to the niobium phosphate network, allowing high mobility of the lithium ion. The structural modifications due to Li insertion have been studied by extended X-ray ...
The local structures of the metal sites in copper metallothionein from Saccharomyces cerevisiae have been investigated by x-ray absorption spectroscopy at the copper and sulfur K edges. Analysis of the EXAFS (extended x-ray absorption fine structure) data indicates that each copper is trigonally coordinated to ...
Fe-K-edge X-ray absorption spectroscopy (XAS) has been used to investigate the electronic and geometric structure of the iron active site in non-heme iron enzymes. A new theoretical extended X-ray absorption fine structure (EXAFS) analysis approach, called GNXAS, has been tested on data for iron model complexes to ...
We have demonstrated the time-resolved measurement of the extended x-ray absorption fine structure (EXAFS) in laser-melted Si foil by using a pump-probe absorption spectroscopy system that utilizes a femtosecond laser-produced-plasma soft x-ray source. By using 100-fs laser irradiation, we observed the transient ...
The bonding of hexanethiols to gold nanoparticles of 1.5, 2.0, and 3 nm was studied using x-ray absorption near-edge spectroscopy (XANES) and extended x-ray absorption fine structure (EXAFS). The XANES spectra revealed that a substantial fraction of weakly bound hexanethiol molecules are present in addition to ...
The bonding of hexanethiols to gold nanoparticles of 1.5, 2.0, and 3nm was studied using x-ray absorption near-edge spectroscopy (XANES) and extended x-ray absorption fine structure (EXAFS). The XANES spectra revealed that a substantial fraction of weakly bound hexanethiol molecules are present in addition to ...
We report x-ray absorption near edge structure (XANES) measurements of four closely related perovskite materials: SrTiO3, CaTiO3, CaZrO3, and SrZrO3. This data is used to address the conceptually important, early EXAFS experiment of Perel and Deslattes. That experiment attempted to distinguish between the then-competing short-range and long-range theories ...
The hydration properties of the bromide aqua ion have been investigated using state of the art density functional theory (DFT) based molecular dynamics with dispersion-corrected atom-centered pseudopotentials for water and classical molecular dynamics simulations. The reliability of the theoretical results has been assessed by comparing the attained structural results with the extended X-ray ...
Fluorescence extended x-ray absorption fine structure spectroscopy (EXAFS) is a commonly used technique in conjunction with x-ray synchrotron radiation for studying the local atomic structure of dilute elements in biological, geological and materials systems. Due to the nature of the EXAFS technique, and the ...
... Title : Multiple Scattering Effects in EXAFS (Extended X-Ray Absorption Fine Structure): Comparison between Theory and Experiment for Pt Metal. ...
X-ray absorption spectroscopy (XAS) is a useful tool for obtaining structural and chemical information about the active sites of metalloproteins and metalloenzymes. Information may be obtained from both the edge region and the extended X-ray absorption fine structure (EXAFS) or post-edge region of the K-edge X-ray ...
The local structure around Ag ions in silver borate glasses g-Ag{sub 2}O{center_dot}nB{sub 2}O{sub 3} (n=2,4) was studied by x-ray absorption spectroscopy at the Ag K edge for temperatures from 77 to 450 K. Extended x-ray absorption fine structure (EXAFS) analysis based on cumulant expansion or multishell Gaussian ...
Mechanically hard ha-C and soft sa-C amorphous carbon films of 2.9 and 2.2 g cm-3 approximate densities were prepared by filtered cathodic arc deposition and analyzed by near-edge x-ray absorption spectroscopy NEXAFS and extended x-ray absorption spectroscopy EXAFS to determine their ...
was founded upon the metals of antiquity, gold (Au), copper (Cu), silver (Ag), lead (Pb), tin (Sn), iron (Fe), and mercury (Hg). Metals were known to the Mesopotamians, Greeks, and Romans. Gold was first discovered about-ray absorption fine-structure (EXAFS) spectroscopy. Her recent interests include the interaction of uranyl
Our research concerns the study of the change in the coordination environment and bond length about transition metals in complexes incorporated in a variety of media using EXAFS spectroelectrochemistry. These systems include: Fe(bipy)3(CIO4)2, Ru(bipy)3C1...
XANES- and EXAFS-measurements at the Ti-, V- and As-K-edge of new and deactivated V/sub 2O5/TiO2-catalysts for the denitrification of the combustion gas produced in the burners of power stations were taken at the 2.5 GeV-Synchrotron beam-line SYLI 2. The ...
X-ray absorption spectroscopy of the iron K edge in both surface sensitive (total reflection) and transmission modes has been applied to a structural investigation of the early stages of the corrosion of stainless steel. Polished AISI 304 stainless steel ...
The principles of experimental methods to study the structure and the hydrogen bonding of hydrated solutes in aqueous solution are presented, and whether theoretical simulations can produce comparable information as the experimental ones is discussed. Two structure methods, extended X-ray absorption fine structure (EXAFS) and large angle X-ray scattering ...
Evidence of a Stable Uranyl Site in Ancient Organic-Rich Calcite S H E L L Y D . K E L L Y , * , E, Stony Brook, New York 11794 The mechanism of uranium (U) incorporation into calcite (calcium carbonate. Extended X-ray absorption fine structure (EXAFS) spectroscopy is uniquely suited to the study of U-calcite
X-ray absorption spectroscopy (XAS) has been used at extensively at Brookhaven National Laboratory (BNL) to study materials and electrodes of several battery systems. The power and the general applicability of the technique is illustrated by studies of several battery materials such as PEO-salt complexes, PbO{sub 2}, and in situ studies of mossy zinc ...
X-ray absorption spectroscopy (XAS) was used extensively at Brookhaven National Laboratory (BNL) to study materials and electrodes of several battery systems. The power and the general applicability of the technique is illustrated by studies of several battery materials such as PEO-salt complexes, PbO2, and in situ studies of mossy zinc deposition in ...
The sorption mechanism of Co on quartz at room temperature has been investigated by an in-depth analysis of published extended X-ray absorption fine structure (EXAFS) spectroscopy and solution chemistry data. In particular, the 3.5-5 mid-range atomic environment of Co has been ...
EPA Science Inventory
X-ray photoelectron spectroscopy (XPS) and extended x-ray absorption fine structure (EXAFS) studies have been undertaken on sodium disilicate glasses containing varying amounts of Fe sub 2 O sub 3 and UO sub 2 . The XPS results enable one to distinguish t...
Arsenate adsorption on amorphous (RuO2�1.1H2O) and crystalline (RuO2) ruthenium oxides was evaluated using spectroscopic and kinetic methods to elucidate the adsorption mechanism. Extended X-ray absorption fine structure spectroscopy (EXAFS) was ...
The effects of alpha irradiation in the rare-earth silicate, Ca2Nd8(SiO4)6O2, was investigated by x-ray diffraction, x-ray absorption near-edge spectroscopy (XANES), and extended x-ray fine structure (EXAFS) techniques. Irradiation with alpha particles em...
X-ray absorption studies along with uv/visible spectroscopy indicate that both the metal center and the macrocycle are involved in the interaction of CO with Fe(III)-TsPc (iron tetrasulfonated phthalocyanine). EXAFS has been used to study the pyrolysis re...
The ESRF has recently started an ambitious project spread over 10 years aimed at an upgrade of the accelerator, beamlines and infrastructure. Through this upgrade, we are proposing a refurbishment of the scanning EXAFS beamline BM29 and of the Energy Dispersive XAS (EDXAS) beamline ID24.
X-ray fluorescence spectroscopy is a widely used method for determining the electronic configuration and local structure of dilute species with high sensitivity. In the dilute limit, and for thin films, the X-ray fluorescence signal is directly proportional to the atomic sub-shell absorption coefficient. However, for concentrated samples, the ...
Deactivation mechanisms of alumina-supported, Ni-based catalysts for tar reforming in biomass-derived syngas were evaluated using extended X-ray absorption fine structure (EXAFS) spectroscopy. Catalysts were characterized before and after catalytic reaction cycles and regeneration procedures, which included oxidation by a mixture of ...
Xanthine oxidase was isolated from unpasteurized buttermilk by a standard procedure. Extended x-ray absorption fine structure (EXAFS) data indicate that reduced xanthine oxidase contains molybdenum in the four valence oxidation state. Curve fitting of the EXAFS data for oxidized xanthine oxidase suggests that there are two different ...
The results of magnetic circular x-ray dichroism (MCXD) measurements and extended x-ray absorption fine structure measurements (EXAFS) of the Fe K-edges of textured Fe(110)/Pd(111) multilayers are reported. The EXAFS results indicates that the iron in the system goes from bcc to a more densely packed system as the thickness of the iron ...
Speciation of copper in the abstraction of nano copper with a room temperature ionic liquid (RTIL) (1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6]) has been studied by X-ray absorption near edge structural (XANES) and extended X-ray absorption fine structural (EXAFS) spectroscopies in the present ...
The results of the investigation of the features of the local structure of quasicrystalline materials by extended X-ray absorption fine structure (EXAFS) spectroscopy with the use of synchrotron radiation are analyzed. The advantages of this method from the point of view of deriving information about the local shifts of the atoms ...
EXAFS (extended X-ray absorption fine structure) and XANES (X-ray absorption near edge structure) techniques have been used to study the structural evolution of nanocomposites constituted of nickel oxide nanoparticles embedded into an amorphous silica matrix during their sol-gel preparation. EXAFS data show that no ...
The proximity of Ca to the Mn cluster of the photosynthetic water-oxidation complex is demonstrated by X-ray absorption spectroscopy. We have collected EXAFS data at the Ca K-edge using active PS II membrane samples that contain approximately 2 Ca per 4 Mn. These samples are much less perturbed than previously investigated ...
The utility of sulfur K-edge X-ray absorption spectroscopy for the determination and quantification of sulfur forms in petroleum asphaltenes has been investigated. Both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra were obtained for a ...
The authors have used x-ray absorption to measure the binding energy, x-ray absorption near-edge structure (XANES), and extended x-ray absorption fine structure (EXAFS) of Pt particles in L-zeolite saturated with H{sub 2} at room temperature and after desorption of H{sub 2} in He. The desorption of H{sub 2} causes ...
X-ray absorption near edge structure spectroscopy has been used to establish the chemical shifts of the technetium K edge in a range of compounds containing Tc in a variety of formal oxidation states. The edge positions span 19.9 eV from Tc metal to NH{sub 4}TcO{sub 4}. Strong correlation between chemical shift and formal oxidation state is observed. ...
Extended x-ray absorption fine structure spectroscopy (EXAFS) is used to investigate the local atomic environment and vibrational properties of plutonium and gallium atoms in the {alpha}{prime} and {delta} phases of a mixed phase Pu-Ga alloy. EXAFS results measured at low temperature compare the structure of the ...
EXAFS and XANES have provided unique and specific structural information for a number of copper proteins. The authors report here the EXAFS and XANES work on superoxide dismutase in some detail to highlight some of the structural information which EXAFS a...
A combination of X-ray absorption spectroscopy (XAS) measurements and quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations has been applied to elucidate detailed information on the hydration structures of Ca(2+) and Cl(-). The XAS spectra (extended X-ray absorption fine structure, ...
The crystal structure and local atom arrangements surrounding Zr atoms were determined for a helium implanted cubic stabilized zirconia (CSZ) using X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) spectroscopy, respectively, measured at glancing angles. The implanted specimen was prepared at a helium fluence ...
Uranium(VI) was sorbed to freshly ground and leached albite in batch and flow-through systems in the pH range 5.0-6.4. The uranium(VI) surface complexes were studied by extended X-ray absorption fine structure (EXAFS) spectroscopy and time-resolved laser-induced fluorescence spectroscopy (TRLFS). The ...
We have developed a cam-drive for quickly tuning the energy of an X-ray monochromator through an X-ray absorption edge for quick extended X-ray absorption spectroscopy (QEXAFS). The data are collected using a 4-channel, 12-bit multiplexed VME analog to digital converter and a VME angle encoder. The VME crate controller runs a real-time ...
Recent developments in the understanding of the biosynthesis of the active site of the nitrogenase enzyme, the structure of the iron centre of [Fe]-hydrogenase and the structure and biomimetic chemistry of the [FeFe] hydrogenase H-cluster as deduced by application of X-ray spectroscopy are reviewed. The techniques central to this work include X-ray ...
Extended X-ray absorption fine structure (EXAFS) backscattering amplitude and phase functions have been calculated from first principles for K and L edges for nearly every element in the periodic table by using a full curved wave formalism. These functions are tabulated for approximately half of the elements from boron through californium. The functions ...
The solvation structure of yttrium (III) in dimethyl sulfoxide has been determined by studying both the extended X-ray absorption fine structure (EXAFS) and the X-ray absorption near edge structure (XANES) regions of the Y K-edge absorption spectra. Although the EXAFS technique provides ...
Copper in a contaminated soil nearby a printed-circuit board waste recycling plant has been extracted onto a microporous molecular sieve (chabazite). The chabazite supported CuO can be used as a chemical looping combustion (CLC) oxygen carrier for CO2 capture. Speciation of copper in the contaminated soil and on the chabazite during CLC has been studied by X-ray absorption ...
Extraction of copper and zinc in the contaminated soil with a room temperature ionic liquid (RTIL) has been studied by X-ray absorption near edge structural (XANES) and X-ray absorption fine structural (EXAFS) spectroscopies in the present work. By the least-square fitted XANES spectra, the major copper and zinc ...
This paper reports on the results of EXAFS investigations (Fe K and Ge K absorption edges) of binary supersaturated nanocrystalline solid solutions Fe{sub 100-x}Ge{sub x} (x = 15-40 at % Ge) prepared by mechanical alloying. The nanocrystalline disordered structure of the single-phase alloys is characterized using X-ray diffraction, Moessbauer ...
Lanthanides/actinides sorption speciation on minerals and oxides by means of time resolved laser fluorescence spectroscopy (TRLFS), extended X-ray absorption fine structure spectroscopy (EXAFS) and density functional theory (DFT) is reviewed in the field of nuclear disposal safety research. The theoretical aspects ...
Nanoparticles (NPs) were formed by sequential ion implantation of Au and Co into thin SiO2. After Au implantation and annealing, Co implantations were carried out at room temperature (RT) and 400 �C, respectively, with no subsequent annealing. The NPs were investigated by means of Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM) and ...
In order to assess the long-term safety of deep radioactive waste repositories, a precise characterization of the different sorption processes on a molecular basis and the exact definition of geochemical boundary conditions for their relevance are of immense importance. Through sorption on various minerals the migration of radionuclides will be hindered and their retention will be ensured. Using ...
Active catalytic phases (metal, mixed metals, oxide or mixed oxides) interacting with oxide support on which the active phase is dispersed can affect the percentage exposed, the morphology of supported particles, the degree of reducibility of cations, etc., in a variety of ways. Our objective is to characterize the physical chemistry of the active phase-oxide support interaction by spectroscopic ...
A new theory of the extended x-ray-absorption fine structure (EXAFS) is presented which avoids the inaccurate approximations of previous ones. It is shown that, in addition to structure determination, EXAFS gives detailed information on the shielding of t...
Extended x-ray absorption fine structure (EXAFS) has been used to investigate the metal environment in a number of metallothioneins (MT). In all cases, the primary coordination sphere consists of sulphur atoms. In some cases, evidence for cluster formatio...
Extended x ray absorption fine structure (EXAFS) is observed as a modulation on the high energy side of an x ray absorption edge. It occurs when the photo-ejected electron wave is scattered by neighboring atoms in a solid, and interference occurs between ...
The manganese sites in chloroplasts, long thought to be involved in photosynthetic oxygen evolution have been examined and partially characterized by x-ray Absorption Spectroscopy (XAS) using synchrotron radiation. The local environment about the manganese atoms is estimated from an analysis of the extended X-ray Absorption Fine ...
Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopy has been used to determine the nearest neighbor environment of Ti in metamict AB2O6-type complex oxides (euxenite and aeschynite structure types) in order to evaluate the effect of alpha-recoil damage of ...
In situ X-ray absorption spectroscopy, ex situ X-ray fluorescence, and X-ray powder diffraction enabled detailed core analysis of phase segregated nanostructured PtRu anode catalysts in an operating direct methanol fuel cell (DMFC). No change in the core structures of the phase segregated catalyst was observed as the potential traversed the current onset ...
To better understand the transportation of copper in the pores of a soil, speciation of copper migrated between micro- and meso-pores at the temperature range of 273-323 K has been studied by in situ X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy. A ...
An embedded layer of metallic clusters of a size of around 10 to 30 A in a ceramic matrix can be produced via ion implantation. We here present some results of the implantation of transition metal ions (Fe, Ni) into AlN. The formation of metallic cluster depends on the chemical nature of the implanted ion and the matrix, while the size of the cluster can be influenced by the number of implanted ...
The microstructure of InxGa1-xN samples grown by electron cyclotron resonance plasma assisted molecular beam epitaxy is studied, as a function of the In concentration, using extended X-ray absorption fine structure spectroscopy (EXAFS), TEM and X-ray diffraction (XRD). The electron and XRD patterns were used in order to determine the ...
A large number of AgI-based fast-ion-conducting glasses have been investigated by K-iodine extended x-ray absorption fine structure spectroscopy (EXAFS) measurements at liquid nitrogen temperature. A general correlation between the I-Ag distance measured by EXAFS and the glass activation energy for dc ionic ...
An embedded layer of metallic clusters of a size of around 10 to 30 � in a ceramic matrix can be produced via ion implantation. We here present some results of the implantation of transition metal ions (Fe, Ni) into AlN. The formation of metallic cluster depends on the chemical nature of the implanted ion and the matrix, while the size of the cluster can be influenced by the number of implanted ...
The long and short range order of chemically prepared Co2FeGa Heusler nanoparticles with various sizes are determined by x-ray diffraction (XRD) and extended x-ray absorption fine structure (EXAFS) spectroscopy. Specifically, EXAFS fittings reveal the size dependent crystal structure and short range order of the ...
Synthetic CdZnTe or 'CZT' crystals can be used for the room temperature-based detection of {gamma}-radiation. Structural/morphological heterogeneities within CZT, such as twinning, inclusions, and polycrystallinity can affect detector performance. We used a synchrotron-based X-ray technique, specifically extended X-ray absorption fine-structure ...
Extended X-ray Absorption Fine Structure (EXAFS) experiments impose stringent requirements on a detection system, due to the need for processing ionizing events at a high rate, typically above of 10Mcps/cm{sup 2}, and with a high resolution, typically better than 300eV. The detection system here presented is being developed targeting these stringent ...
Effect of nitrogen and carbon doping on the structure of GeTe has been investigated using x-ray diffraction and extended x-ray absorption fine structure (EXAFS) spectroscopies. While Bragg diffraction which probes the global structure exhibits a clear transition upon doping from the rhombohedral phase to the cubic (rocksalt) phase, the ...
Isoelectric point isoforms of a metalloprotein, copper-zinc superoxide dismutase (CuZnSOD), separated on electrophoresis gels were analyzed using X-ray Absorption Spectroscopy. Mutations of this protein are involved in familial cases of amyotrophic lateral sclerosis. The toxicity of mutants could be relied to defects in the metallation state. Our purpose ...
The short-range order and the crystalline structure of AuCu and AuAg alloy nanoclusters obtained by sequential ion implantation in silica are investigated by extended X-ray absorption fine structure (EXAFS) spectroscopy and by grazing incidence X-ray diffraction (GIXRD). While in the case of AuAg alloy the nearest neighbor interatomic ...
An alumina-supported rhodium catalyst has been studied with EXAFS. After reduction and evacuation, oxygen was admitted at 100 and 300 K. EXAFS spectra of the catalyst after oxygen admission at 100 K indicated the beginning of oxidation. At 300 K only a small part of the rhodium particles remained metallic and this metallic kernel was partly covered with ...
Au nanocrystals (NCs) fabricated by ion implantation into thin SiO{sub 2} and annealing were investigated by means of extended x-ray absorption fine structure (EXAFS) spectroscopy and transmission electron microscopy. A bond length contraction was observed and can be explained by surface tension effects in a simple liquid-drop model. ...
Au nanocrystals (NCs) fabricated by ion implantation into thin SiO2 and annealing were investigated by means of extended x-ray absorption fine structure (EXAFS) spectroscopy and transmission electron microscopy. A bond length contraction was observed and can be explained by surface tension effects in a simple liquid-drop model. Such ...
... This structure is analogous to extended X-ray absorption fine structure (EXAFS), and can be interpreted in terms of interatomic distances in the ...
A structural study based on EXAFS, FTIR, and optical absorption spectroscopies has been conducted on a photogenerated, metastable state of cyclopentadienylnickelnitrosyl (CpNiNO) produced by a reversible photochemical reaction. The photogenerated, metastable state with distinctively different EXAFS, IR, and optical ...
X-ray spectroscopy has long been used to elucidate electronic and structural information of molecules. One of the weaknesses of x-ray absorption is its sensitivity to all of the atoms of a particular element in a sample. Through out this thesis, a new technique for enhancing the site- and spin-selectivity of the x-ray absorption has ...
Dimethyl gold complexes bonded to partially dehydroxylated MgO powder calcined at 673 K were synthesized by adsorption of Au(CH3)2(acac) (acac is C5H7O2) from n-pentane solution. The synthesis and subsequent decomposition of the complexes by treatment in He or H2 were characterized with diffuse reflectance Fourier transform infrared (DRIFT), X-ray absorption near edge ...
X-ray absorption spectroscopy (XAS) has become a prominent tool for the element-specific analysis of transition metals at the catalytic center of metalloenzymes. In the present study the information content of X-ray spectra with respect to the nuclear geometry and, in particular, to the electronic structure of the protein-bound metal ions is explored using ...
Plant hyperaccumulation of the essential nutrient manganese (Mn) is a rare phenomenon most evident in the Western Pacific region, and differs from hyperaccumulation of other elements. Mn hyperaccumulators employ a variety of species-dependent spatial distribution patterns in sequestering excess foliar Mn, including primary sequestration in both nonphotosynthetic and photosynthetic tissues. This ...
Absorption measurements above the K edges of the low-Z atoms, C, N, O, and F, are discussed, which utilize 250--1000-eV synchrotron radiation. The paper emphasizes experimental procedures of soft x-ray absorption and extended absorption fine structure (EXAFS) measurements as well as applications and future ...
The approximate barium X-ray atomic absorption in the energy region of L-edges is reconstructed from the absorption spectrum of an aqueous solution of BaCl(2). The result is corroborated by comparison with pure atomic absorption spectra of neighbour elements Xe and Cs. The application of the atomic absorption ...
Detailed analyses of crystalline, hydrated, and precipitated strontium compounds and an aqueous strontium solution by synchrotron extended X-ray absorption fine structure (EXAFS) were used to quantify local thermal and static disorder and to characterize strontium coordination in a variety of oxygen-ligated bonding environments. Analysis of anharmonic ...
Extended X-ray absorption fine structure (EXAFS) spectroscopy at the Zn - K edge is applied for the study of the bonding geometry of Zn in human nails. The studied nail clippings belong to healthy donors and donors who suffer from lung diseases. Fitting of the first nearest neighboring shell of Zn reveals that it is bonded with N and ...
We have used picosecond and nanosecond, hard x-ray pulses (5-15 keV) generated by a laser driven x-ray diode to study transient and excited state structures of liquids and solids by means of x-ray diffraction and extended x-ray absorption fine structure (EXAFS) techniques. The changes in the structure of the ultrafast intermediates with picosecond time ...
We have investigated the effect of ion irradiation on the structure and morphology of Au nanocrystals (NCs) fabricated by ion beam synthesis in a thin SiO2 layer on a Si substrate. Extended X-ray absorption fine structure (EXAFS) spectroscopy measurements show a significant drop in the average Au Au coordination, as well as a loss of ...
Lustre is one of the most important decorative techniques of the Medieval and Renaissance pottery of the Mediterranean basin, capable of producing brilliant metallic reflections and iridescence. Following the recent finding that the colour of lustre decorations is mainly determined by copper and silver nanoclusters dispersed in the glaze layer, the local environment of copper and silver atoms has ...
We have used small-angle X-ray scattering (SAXS) and extended X-ray absorption fine structure (EXAFS) spectroscopy to investigate Au nanocrystals (NCs) fabricated by high dose ion implantation into thin SiO2 and subsequent annealing at different temperatures. Size distributions were determined from SAXS and structural parameters were ...
Short-range structural disorder of the high-{kappa} dielectric BaTaO{sub 2}N is revealed by the analysis of the extended x-ray-absorption fine-structure (EXAFS) spectroscopy measured at the Ta L{sub III} edge. Although previous neutron, x-ray, and electron diffraction studies have shown BaTaO{sub 2}N to crystallize in a ...
The nature of Ni-hydroxide precipitates on pyrophyllite were reexamined by analytical electron microscopy (AEM), high-resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), powder X-ray diffraction (PXRD), and extended X-ray absorption fine structure (EXAFS) spectroscopy. Chemical analysis of ...
Gold clusters deposited by evaporation on a Mylar substrate in many superimposed layers have been studied by EXAFS (extended x-ray-absorption fine-structure) spectroscopy at T=28 K. For such clusters, the first shell signal of the EXAFS spectrum has been compared with the corresponding crystal data used for the ...
In order to determine the structural basis for the activity of transition metals exchanged into zeolite frameworks, a series of extended X-ray absorption fine structure (EXAFS) measurements have been made. In the particular case of Rh, it has been shown that solutions of (RhCl(NH/sub 3/)/sub 5/)Cl/sub 2/ exchanged with Na-X form a highly active catalyst ...
Studies of amorphous (a-) semiconductors have been driven by technological advances as well as fundamental theories. Observation of electrical switching, for example, fueled early interest in a-chalcogenides. More recently a-chalcogenide switching has been applied successfully to programmable memory devices as well as DVD technology where the quest for the discovery of better-suited materials ...
We have studied the electrical and structural properties of InP implanted with Ge ions (2[times]10[sup 15]/cm[sup 2]). The implantation was performed at both room temperature (RT) and liquid nitrogen temperature (LNT). After annealing at 850 [degree]C for 5 s, both sets of samples exhibited [ital n]-type conductivity. The [ital n]-type activation efficiency in the RT implanted sample was about a ...
Riboflavin Binding Protein (RBP) binds copper in a 1:1 molar ratio, forming a distinct well-ordered type II site. The nature of this site has been examined using X-ray absorption and pulsed electron paramagnetic resonance (EPR) spectroscopies, revealing a four coordinate oxygen/nitrogen rich environment. On the basis of analysis of the Cambridge Structural ...
Mononuclear rhodium complexes incorporating two ethylene ligands and anchored to dealuminated zeolite Y by two Rh-O bonds were characterized by transient extended X-ray absorption fine structure (EXAFS) spectroscopy and infrared (IR) spectroscopy as they were converted in the presence of H{sub 2}. ...
PubMed Central
Extended x-ray-absorption fine-structure spectroscopy (EXAFS) has been used to determine the position of Zr within the unit cell of Sm{sub 2}Co{sub 17}. Induction-melted Sm{sub 2}Co{sub 17}:Zr ternary alloys, aged at 1180 {degree}C, then quenched, consisted of intimately mixed H2:17 and R2:17 having Zr in solid solution as well some ...
The magnetic and electric properties of ferrites are influenced by the cation distribution within the crystalline spinel lattice. Methods such as extended x-ray-absorption fine structure (EXAFS) have been used to determine cation occupancies within the crystalline structure of materials such as manganese zinc ferrite (MZFO); however, it is not practical to ...
Field plots were established at a timber treatment site to evaluate remediation of Cu contaminated topsoils with aided phytostabilization. Soil containing 2600 mg kg?� Cu was amended with a combination of 5 wt% compost and 2 wt% iron grit, and vegetated. Sequential extraction was combined with extended X-ray absorption fine structure (EXAFS) ...
The distribution of {sup 237}Np(V) between aqueous NaHCO{sub 3} solutions and U(VI) hydroxide solids was investigated. Experiments were initiated by addition of U solids to Np solutions and by coprecipitation of U and Np. Analysis by U L{sub III} extended X-ray absorption fine structure (EXAFS) spectroscopy and infrared ...
The characterization of an iron-containing natural zeolitic sample from the deposit of Tasajeras (Cuba) has been carried out by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS),57Fe M�ssbauer spectroscopy and Fe K-edge X-ray ...
... Abstract : First application of extended x-ray absorption fine structure (EXAFS) technique to measurements of interatomic distance, local order, and ...
... of EXAFS (Extended xray absorption fine structure ... have recorded the extended x-ray-absorption fine structure ... above the carbon K edge for diamond ...
To better understand the unique features and structural implications of An-soft donor interactions, we used solvent extraction, extended x-ray absorption fine structure (EXAFS), and optical spectroscopy to study both the lanthanide and actinide complexes of a series of dialkylphosphinic acid extractants, ...
The unique features of X-ray absorption spectroscopy allow investigations of nanosized catalysts for fuel cells under working conditions. We present the results of an experiment carried out on a low Pt content electrocatalyst supported by a mesoporous heteropolyacid salt and used at the cathode of a proton exchange membrane fuel cell (PEMFC). The analysis ...
Glassy As25Si40Te35 has been studied by x-ray and neutron diffraction as well as x-ray absorption spectroscopy (EXAFS) at As and Te K-edges. Simultaneous modelling of the four independent measurements by means of the reverse Monte Carlo (RMC) simulation technique allowed the separation of partial pair distribution functions and ...
X-ray absorption studies along with uv/visible spectroscopy indicate that both the metal center and the macrocycle are involved in the interaction of CO with Fe(III)-TsPc (iron tetrasulfonated phthalocyanine). EXAFS has been used to study the pyrolysis reaction of Fe-Pc and Co-Pc on Vulcan XC-72 carbon at 400, 600 and 900/sup 0/C. ...
We describe the characterization of an unknown and difficult to identify but geochemically and environmentally significant MnOx structure produced by a freshwater bacterium, Leptothrix discophora SP-6, using combined transmission electron microscopy (TEM), extended X-ray absorption fine structure (EXAFS), and UV Raman spectroscopy. The ...
The previously reported work on the determination of the role of sulfur donor ligand in the function of heme proteins is very briefly surveyed. The results of studies in which x-ray absorption fine structure (EXAFS) spectroscopy has been employed for the structural analysis of sulfur-ligated heme complexes are reported. These results ...
The structures of small, robust metal clusters on a solid support were determined by a combination of spectroscopic and microscopic methods: extended X-ray absorption fine structure (EXAFS) spectroscopy, scanning transmission electron microscopy (STEM), and aberration-corrected STEM. The samples were synthesized from [Os(3) (CO)(12) ] ...
Cu nanocrystals (NCs) were produced by multiple high-energy ion implantations into 5-{mu}m-thick amorphous silica (SiO{sub 2}) at liquid-nitrogen temperature. The Cu-rich SiO{sub 2} films were subsequently annealed to reduce irradiation-induced damage and promote NC formation. The NC size distribution and structure were studied utilizing a combination of Rutherford backscattering ...
Interaction of heavy metals with clay minerals can dominate solid-solution reactions in soil, controlling the fate of the metals in the environment. In this study we used powdered and polarized extended X-ray absorption fine structure (EXAFS) spectroscopy and X-ray absorption near edge ...
Magnetic circular dichroism (MCD) studies at K and L edges using hard and soft x rays are presented. The relation of this universal phenomenon in the x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) regions to local magnetic structures in the case of 3d and 4f elements is illustrated. ...
In order to learn about in situ structural changes in materials at subseconds time scale, we have further refined the techniques of quick extended x-ray absorption fine structure (QEXAFS) and quick x-ray absorption near edge structure (XANES) spectroscopies at beamline X18B at the National Synchrotron Light Source. The channel cut Si ...
Speciation of copper in a copper-rich chemical-mechanical polishing sludge during electrokinetic treatment has been studied by in situ extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) spectroscopy. The least-squares-fitted XANES spectra indicate that the main copper ...
X-ray-absorption spectroscopy has been used to study the high-T/sub c/ superconductor YBa/sub 2/Cu/sub 3/O/sub 7/ on all three metal elements. The structure determined is consistent with diffraction results, except for some slight differences. Analysis of the yttrium K-edge x-ray-absorption fine-structure (EXAFS) ...
This work investigates local atomic and electronic structures of PbZr0.52Ti0.48O3 (PZT) thin films with <001>, <101>, and <111> orientations using extended x-ray absorption fine structure (EXAFS) and x-ray absorption near-edge structure (XANES) spectroscopy with ? = 0� and 70� incident angles. ...
Our previous extended-X-ray-absorption-fine-structure (e.x.a.f.s.) study has shown that the probable iron environment in chicken ovotransferrin involves two low-Z ligands (consistent with phenolate linkages) at 0.185(1) nm and four low-Z ligands at 0.204(1) nm [Garratt, Evans, Hasnain & Lindley (1986) Biochem. J. 233, 479-484]. Herein we provide ...
LiFePO4 composite was synthesized by both solid state and hydrothermal methods. The physical properties of the as-prepared lithium iron phosphates were characterized by X-ray diffraction while electrochemical properties were measured with charge/discharge experiments. X-ray absorption spectroscopy (XAS) was performed to investigate the local structure ...
A software package for the analysis of X-ray absorption spectroscopy (XAS) data is presented. This package is based on the IFEFFIT library of numerical and XAS algorithms and is written in the Perl programming language using the Perl/Tk graphics toolkit. The programs described here are: (i) ATHENA, a program for XAS data processing, (ii) ARTEMIS, a program ...
... high resolution IR absorption spectroscopy in ... Descriptors : *HYDROGEN, *ABSORPTION, *SOLID ... PROPERTIES, INFRARED SPECTROSCOPY ...
Anharmonicity in the lattice vibrations of oxygens in UO(2) has been examined by using EXAFS of the U L(III) absorption edge. While the EXAFS determined U-U distance of 3.89 A closely matches the crystallographic separation, the U-O distance of 2.43 A is ...
Silver K-edge X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) data were collected and analyzed to characterize silver (Ag) environments in borosilicate and Ca-aluminoborate glass formulations developed as potential candidates for the immobilization of certain nuclear wastes. Silver is ...
Investigations of the darkening phenomenon of copper resinate observed in a XV century easel painting were carried out by X-ray absorption spectroscopy (XAS) at the GILDA beamline of the European synchrotron radiation facility (ESRF, Grenoble, France). X-ray absorption near edge structure and extended X-ray ...
Hole-doped perovskites such as La{sub 1-x}Ca{sub x}MnO{sub 3} present special magnetic and magnetotransport properties, and it is commonly accepted that the local atomic structure around Mn ions plays a crucial role in determining these peculiar features. Therefore experimental techniques directly probing the local atomic structure, like x-ray absorption ...
The sorption capacity of montmorillonite clay minerals for small cations, such as Ni2+, can be greatly enhanced by modifying the clay mineral with Al(III). In this study, the mechanisms of Ni uptake by Al-modified montmorillonite were studied using extended x-ray absorption fine structure (EXAFS) spectroscopy of powders and polarized ...
A series of alkaline uranyl carbonates, M[UO{sub 2}(CO{sub 3}){sub 3}].nH{sub 2}O (M=Mg{sub 2}, Ca{sub 2}, Sr{sub 2}, Ba{sub 2}, Na{sub 2}Ca, and CaMg) was synthesized and characterized by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) after nitric acid digestion, X-ray powder diffraction (XRD), and thermal analysis (TGA/DTA). ...
A series of alkaline uranyl carbonates, M[UO2(CO3)3]�nH2O (M=Mg2, Ca2, Sr2, Ba2, Na2Ca, and CaMg) was synthesized and characterized by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) after nitric acid digestion, X-ray powder diffraction (XRD), and thermal analysis (TGA/DTA). The molecular structure of these compounds was ...
Smalt was commonly used as a pigment by artists between the 16th and 18th centuries. It is a powdered blue potash glass colored by cobalt ions and often degrades causing dramatic changes in the appearance of paintings. The aim of the work presented in this paper was to investigate the changes in the structure and environment around the cobalt ion on deterioration, to further our understanding of ...
Applying EXAFS spectroscopy, the hydrophobic interaction has been investigated, which is of great significance in biology and biochemistry. The model systems used for these studies are solutions of rare gases in water, ethanol and n-propanol. A multichann...
The accumulation of iron and arsenic from aqueous solution by lettuce leaves biomass was investigated using M�ssbauer and EXAFS spectroscopic techniques. M�ssbauer spectroscopy results show that iron is oxidized during sorption while EXAFS results indicate that iron is coordinated by approximately 6 oxygen and 2 carbon atoms while ...
The primary purpose of this research was to develop the phenomenon of extended x-ray absorption fine structure (EXAFS) as a technique for investigating the structure of non-crystalline materials, particularly amorphous semiconductors. The EXAFS work on am...
In many cases the fluorescence EXAFS signal is contaminated with fluorescence from nearby elements. If this fluorescence is of lower energy than the element of interest, x-ray filters are not effective. One method for dealing with this problem is the doub...
