... Title : ON THE THEORY OF THE FINE STRUCTURE OF THE X RAY ABSORPTION SPECTRA OF IONS IN SOLUTIONS. ...
DTIC Science & Technology
... Title : EXTENDED X-RAY ABSORPTION FINE STRUCTURE: A MODERN STRUCTURAL TOOL IN MATERIALS SCIENCE. Corporate Author : ...
... statistical fine structure (SFS) in the inhomogeneously broadened optical absorption of pentacene in ... size of the SFS varies as the square root of the ...
... 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 ...
... i059-02 (1953) On the Theory of the Fine Structure the X-Ray Absorption Spectra of ions in Solutions E. Ye. Vainshtein ...
... This structure is analogous to extended X-ray absorption fine structure (EXAFS), and can be interpreted in terms of interatomic distances in the ...
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...
National Technical Information Service (NTIS)
... The first result, direct detection of intrinsic static absorption fine structure on a ... the spectral density of absorbers which scale as the square root of the ...
A new approach to the analysis of x-ray absorption fine structure (XAFS) data is presented. It is based on the use of radial distribution functions directly calculated from a single-particle ion hamiltonian containing model potentials. The starting point ...
A general theory of the fine structure observed on the high-energy side of the K-absorption edge (EXAFS) is presented. The form of the theory presented is useful when the excited atom is not too highly ionized and the potential is approximately sphericall...
... STUDY OF BOND CONSTRAINTS IN GE-SB-TE ALLOYS ... Extended X-ray Absorption Fine Structure Study of Bond Constraints in Ge-Sb-Te Alloys ...
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...
The first direct measurement of the fluorine-atom ground state fine structure transition, using diode laser absorption spectroscopy, is reported. The fine structure absorption line position (spin-orbit energy splitting), measured with high precision relat...
The fluctuations of absorption coefficient which appear on the high energy side of x-ray absorption edges have been separated historically and physically into two different but similar effects. The structure in and near the edge (Kossel structure) has bee...
... The fine structure correlates with this absorptive capacity in the following ways: (1) keratin- ization is partial; (2) the lesser degree of keratinization is ...
... TIME, PULSES, RADIATION, SYNCHROTRONS, CONTINUOUS SPECTRA, XENON LAMPS, INTEGRATION, MATERIALS, TARGETS. ...
... SPECTRA, ATOMIC ENERGY LEVELS, ELECTRON TRANSITIONS, SELECTION RULES(PHYSICS), MAGNETIC MOMENTS, DIPOLE MOMENTS ...
... Accession Number : AD0634874. Title : DETERMINATION OF INTERATOMIC DISTANCES FROM X-RAY ABSORPTION FINE STRUCTURE. ...
Strong interstellar absorption lines of C I, arising from the two excited fine-structure levels, are
NASA Technical Reports Server (NTRS)
... 47 MICRONS OZONE BANDS, WITH CONSIDERATION OF THEIR FINE STRUCTURE-ATMOSPHERIC AND OCEANIC PHYSICS, V5, NO9, P514 ...
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 ...
Energy Citations Database
Since the first experiment on an intense synchrotron radiation source ten years ago, EXAFS (Extended X-ray Absorption Fine Structure) and XANES (X-ray Absorption Near Edge Structure), have become a routine technique for investigating the environment of me...
A particle-in-a-box approximation to the problem of x-ray absorption fine structure has been successful in predicting many features of the effect. The theory successfully accounts for the extended fine structure observed on any x-ray absorption edge in cr...
... resonance (EPR), and (7)Li solid state nuclear magnetic resonance (NMR ... extended x-ray absorption fine structure shows that the local symmetry of ...
... Accession Number : AD0693193. Title : POINT SCATTERING THEORY OF X-RAY K-ABSORPTION FINE STRUCTURE,. ...
... Title : LASER-EXAFS: FAST EXTENDED X-RAY ABSORPTION FINE STRUCTURE SPECTROSCOPY WITH A SINGLE PULSE OF LASER ...
The fine structure of the K-absorption spectrum of a Ge single crystal was investigated with 90% polarized radiation. A single-crystal spectrometer and a fine focus x-ray tube were used. Absorption curves were obtained up to 300 ev from the main edge for five different positions of the ...
The fine structure of the argon K absorption edge was observed by measuring the response of an argon-filled proportional counter as a function of the incident x-ray energy. It is shown that the response of a thin counter is proportional to mu /sub K/, the K-shell contribution to the linear absorption ...
... x-ray absorption fine structure (EXAFS), infra-red and Raman spectroscopy, low temperature specific heat, and electron spin resonance (ESR). ...
The fine structure of the K absorption spectra of nickel and iron in Ni- Fe alloys was studied. The results are given relative to the displacements of the Ki points of the principal discontinuities and of the maxima and minima of the fine structure determined by the variation of the ...
The thesis presents extended X-ray absorption fine structure, EXAFS, and large angle X-ray scattering, LAXS, techniques; instrumentation, data collection and reduction, and applications. These techniques have been used to determine the structures of magne...
We have applied several X-ray absorption fine structure (XAFS) techniques to study materials which have been structurally modified in a variety of ways. These techniques include conventional absorption and fluorescence methods as well as electron yield at...
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...
We report measurements of extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge structure (XANES) of the L edge of iodine in the polymer electrolytes PPO8NaI, PPO8LiL, and PEI10NaI. The EXAFS indicates a disordered environment fo...
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 ...
The authors applied Fourier analysis to our point-scattering theory of x-ray absorption fine structure to invert experimental data formally into a radial structure function with determinable structural parameters of distance from the absorbing atom, numbe...
... X-ray absorption fine structure (XAFS) spectroscopy is an ... were examined initially by powder X-ray diffraction (XRD ... around the Ni K-edge (8333 eV ...
Synchrotron radiation can be used in Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES) experimental modes to extract information concerning chemical speciation of elements at trace concentration levels. The ...
Absorption Fine Structure (NEXAFS) or X-ray Absorption Near-Edge Structure ( XANES), .... Japanese Journal of Applied Physics Part 2-Letters 33 (1b) pp.l125- ...
NASA Website
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...
Near edge x-ray absorption fine structure (NEXAFS) and infrared reflection-absorption spectroscopy (IRRAS) have been used to study the orientational behavior of thin films of poly(3-methylthiophene) electrochemically polymerized on a platinum surface. Cle...
The structures of initial and final products of bromoalkanes' photodisociation reaction in cyclohexane solution have been measured with a bond length accuracy of 0.02 ? by means of ultrafast time-resolved extended x-ray absorption fine structure spectroscopy. The photoredaction mechanism is also discussed.
PubMed Central
... Experimental K-edge NEXAFS (near edge X-ray absorption fine structure) data for solid Ne are compared with theoretical results. ...
... Investigations of the absorption spectrum of nitric oxide in polar solvents led to the discovery of a band with well resolved vibrational fine structure ...
... The calculations are very similar to X-ray absorption fine structure (XAFS) calculations. ... panel is for the region around the boron K edge and the ...
... Recently, Near Edge X-ray Absorption Fine Structure (NEXAFS ... Using the highly polarized x-ray beam of the ... The carbon k-edge NEXAFS spectra of ...
Jun 16, 2011 ... Title: Novel visualization studies of lignocellulosic oxidation chemistry by application of C-near edge X-ray absorption fine structure ...
Treesearch
... X-ray absorption fine structure (EXAFS) measurements on ... high purity copper, gold, and cobalt wires with ... 8. Ignatov, AU and others, The Location of ...
... Title : Multiple Scattering Effects in EXAFS (Extended X-Ray Absorption Fine Structure): Comparison between Theory and Experiment for Pt Metal. ...
near-edge x-ray absorption fine-structure (NEXAFS) spectroscopy, allows for quantitative determination of submicron polymer blend composition. At a lateral resolution of 50 nm,...
Science.gov Websites
... Keywords: Polymer electrolytes; Poly(propylene oxide); Poly(ethylene imine). Descriptors : *IODINE, *POLYMERS, *SALTS, *COMPLEX ...
... on electronic optical properties of amorphous alloys, optical properties, x ray absorption fine structure and magnetooptic Kerr effect of transition and ...
It is shown that the splitting of the resonance transition in the low-temperature absorption and luminescence spectra of cubic crystals of uranyl compounds should be interpreted as Davydov splitting. (AIP)
... SPECTROSCOPY, SEMICONDUCTORS, PHOTONS, TELLURIUM ALLOYS, GERMANIUM ALLOYS, ANTIMONY ALLOYS, ELECTRONICS, X RAY ...
... The following component part numbers comprise the compilation report: ADPO11500 ... is only coordinated with S with a coordination number CN = 4 ...
... The fine structure of the X-ray absorption spectra of iron and manganese in ferrites with various quantities of additions of rare-earth elements was ...
DOES THE FINE STRUCTURE CONSTANT VARY? A THIRD QUASAR ABSORPTION SAMPLE CONSISTENT WITH VARYING of New South Wales, Sydney, NSW 2052, Australia Abstract. We report results from a third sample of quasar structure in quasar absorbing clouds. However, kinematics are unlikely to impact significantly
E-print Network
The application of near-edge surface, extended x-ray absorption fine structure to the study of a clean surface is reported. Direct evidence is found for surface recrystallization of ion-damaged (amorphized) Si, whereas no such evidence is seen for evaporated (amorphous) Si. The procedures described here are applicable to almost all ...
The Surface Extended X Ray Absorption Fine Structure (SEFAFS) spectrum of an electrochemically deposited ad-layer of copper on a gold (111) electrode immersed in solution and under potential control was obtained by employing fluorescence detection and gra...
The combination of glancing angle x-ray absorption fine structure (XAFS) and x-ray reflectivity measurements provide detailed structural information about interfaces. Results from transition-metal/Al interfaces are used to illustrate the capabilities of t...
Electronic and structural aspects of composite nickel-cobalt hydrous oxides have been examined in alkaline solutions using in situ X-ray absorption fine structure (XAFS). The results obtained have indicated that cobalt in this material is present as cobal...
We use relativistic Hartree-Fock and configuration-interaction methods to calculate the dependence of transition frequencies for singly ionized cobalt on the fine structure constant. The results are to be used in the search for variation of the fine structure constant in quasar absorption ...
NASA Astrophysics Data System (ADS)
Experimental results on fine-structure transitions occurring in collisional redistribution of far--off-resonant radiation are presented. Measurements on Na-Ar atomic collisions illustrate that electronically nonadiabatic transitions occurring in the final state, following absorption, are important for describing the redistribution process. The results also ...
A novel code for the analysis of extended x-ray absorption fine structure (EXAFS) data collected in total reflection mode (reflEXAFS) is presented. The procedure calculates the theoretical fine structure signals appearing in the reflectivity spectrum starting from the ab initio EXAFS ...
X-ray absorption measurements (X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS)) above all the three L edges of Sm are employed to study the mixed valence in Sm1-xScxS alloys (x
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 ...
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 ...
EXAFS (Extended X-ray Absorption Fine Structure) and XANES (X-ray Absorption Near Edge Spectra) applied to some problems of biophysics interest are discussed. (Atomindex citation 16:067442)
... method allows the local environment of X-ray absorbing atoms in ... films at the sulfur (S) K-edge and, as ... Argon absorption was found to limit the data ...
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...
Extended x-ray absorption fine-structure (EXAFS) data collected in the fluorescence mode are susceptible to an apparent amplitude reduction due to the self-absorption of the fluorescing photon by the sample before it reaches a detector. Previous treatments have made the simplifying assumption that the effect of the EXAFS on the ...
DOE Information Bridge
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...
The surface chemistry of hydrocarbons, particularly aromatic hydrocarbons, adsorbed on Pt(111) was investigated by Thermal Desorption Spectrometry (TDS) and Near Edge X-ray Absorption Fine Structure (NEXAFS). The utility of NEXAFS in the investigation of ...
Near-edge x-ray absorption fine structure (NEXAFS) is used to examine the chemical bonding in boron and boron-nitride films sputter deposited from a fully-dense, pure boron target. Reactive sputtering is used to prepare the boron-nitride and multilayered ...
Near-Edge X-ray Absorption Fine Structure Spectroscopy of MDI and TDI Polyurethane Polymers Stephen) to differences in key chemical components of polyurethane polymers is presented. Carbon 1s NEXAFS spectra of polyurethane polymers made from 4,4-methylene di-p-phenylene isocyanate (MDI) and toluene diisocyanate (TDI
Identification using the extended x-ray absorption fine structure technique shows that nickel impurities found in synthetic diamonds exist as fcc Ni and contain an estimated amount of 2.7 +- 1.3 at.% carbon in solution.
Extended x-ray absorption fine structure (EXAFS) model functions have been calculated for the LIII edge in Pt metal. All single, double and triple scattering contributions were taken into account, using a recently developed multiple scattering formalism. ...
It has been shown by recording the derivative absorption spectra of various different substances that it is possible to resolve the fine structure which cannot be obtained when the spectra are recorded using conventional spectrophotometers. This method is particularly valuable in the study of complex formation by ions of the ...
EXAFS (Extended X-ray Absorption Fine Structure) studies of cubic (ZrO sub 2 )/sub 1-x/(Y sub 2 O sub 3 )/sub x/ are reported for the concentration range 0.09
The absorption spectra of water down to 185 m mu was observed without finding the fine structure described by Golding. The results were checked on a vacuum grating spectrophotometer and extended down to 180 m mu using silica cells. The absorbance of water rose nearly linearly down to at least 150 m mu with no trace of ...
X-ray Photo Emission Electron Microscopy (X-PEEM) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy were applied to study the properties of amorphous hard carbon overcoats on disks and sliders, and the properties of the lubricant. The mo...
The fine structures at the absorption L edges of antimony in SbSI were observed in the paraelectric and ferroelectric phases. The X-ray absorption near edge structures at the L1 and L3 edges do not show any difference in shape and position due to the phase transition, indicating the lack of ...
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...
The results of optical absorption measurements on pure AgCl and AgBr are reported and compared with the wavelength dependence of photoconductivity in these materials. Detailed structure consisting of low level absorption-tails and several shoulders was found at various temperatures down to 4.2 deg K. The data were analyzed in ...
X-ray absorption fine structure (XAFS) spectroscopy has been used to investigate the valence states and molecular structures of sulfur (S), chromium (Cr), arsenic (As), and zinc (Zn) in fine particulate matter (PM) separated from coal flyash produced in a realistic combustion sys...
EPA Science Inventory
Extended X-ray absorption fine-structure spectra of yttrium-iron garnet, measured near the absorption edges of iron and yttrium at the Kurchatov synchrotron radiation source are reported. Numerical simulation of the X-ray absorption near-edge structure of these spectra is performed and good ...
We discuss directional fine structure in absorption of white x rays for tomographic imaging of crystal structure at the atomic level. The interference between a direct x-ray beam and the secondary waves coherently scattered inside a specimen modifies the total wave field at the position of the absorbing atoms. For ...
The initial ordered chemisorption stage of oxygen on Al(111) has been investigated using polarization-dependent surface extended x-ray absorption fine-structure measurements above the O K absorption edge. The O-Al bond length in the threefold hollow adsorption site has been determined to be 1.79 +- 0.05 A. A strong polarization ...
The local structure of monoclinic, monohydrate, hexagonal, and pyrochlore WO3 phases was investigated by the extended x-ray absorption fine structure spectroscopy as preliminary studies of model compounds of amorphous and thin film WO3 based electrochromic species. In the four cases, we found a large W-O ...
PubMed
Variable incidence angle X-ray absorption fine structure (VIAXAFS) spectroscopy offers a non-destructive ability to investigate film nano-structures. This technique was applied, spanning sample-beam angles from a grazing to normal incidence on a film obtained by zirconia sputtering on flat sample of stainless ...
The first-principles band structure calculations are carried out to interpret the spectral fine structure of the near-edge X-ray absorption fine structure (NEXAFS) spectrum of PdO at the O K-edge by the full-potential augmented plane wave plus local orbitals (APW+lo) ...
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 ...
A rapid fine energy tuning method for a double-crystal monochromator (DCM) is developed by combining a feedback control system with a phase sensitive detector. This method maintains both a parallel angle between the first and second crystals of the DCM and the peak of the rocking curve. The method is used to perform a continuous energy scan of the DCM without readjustment of ...
One of the long term research goals has been to attain a quantitative theory of deep core X-ray spectroscopies. These spectroscopies include X-ray absorption fine structure (XAFS), X-ray absorption near edge structure (XANES), X-ray magnetic circular dich...
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...
K-absorption edge of coordinated ions exhibits a fine structure (through the use of XANES, or x-ray absorption near edge structures) that reflects the electronic repartition and the chemical reactivity of these ions. Comparative analysis of iron K-absorption-edge shape for ...
The fluorescence detected surface EXAFS of silver, underpotentially deposited from aqueous solutions of silver ion (HCIO4 electrolyte) on Au(111) electrodes was used to investigate the local structure of the adsorbate. Analysis of the data indicates that ...
Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibil...
This report discusses work on the characterization by extended x-ray absorption fine structure spectroscopy, structures formed on the surface of partially dehydroxylated magnesium oxides by adsorption of (HRe(CO){sub 5}).
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 ...
An approach to X-ray attenuation correction for diffraction anomalous fine-structure (DAFS) measurements is presented, taking into account energy-dependent secondary extinction effects. A numerical model based on the kinematical theory of diffraction is presented. This model is exemplified by DAFS measurements of the Zr 0002 reflection intensities for energies in the vicinity ...
Fine structure consisting of more than twenty sharp lines has been observed near the absorption edge of silver-doped ZnTe single crystals containing dislocation loops. Possible explanations for the observed spectrum based on excitons bound to the dislocation loops or on "dangling bonds" associated with the presence of the dislocation ...
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...
We study the temperature evolution of aluminum nanoparticles generated by femtosecond laser ablation with spatiotemporally resolved x-ray-absorption fine-structure spectroscopy. We successfully identify the nanoparticles based on the L-edge absorption fine structure of the ablation plume in ...
We have investigated the local atomic environment of the Ga atoms in an InxGa1-xN single quantum well structure using Optically Detected Extended X-ray Absorption Fine Structure (OD-EXAFS). A comparison of the OD-EXAFS data with a theoretical model shows the technique to be site selective for this particular ...
The in vivo coordination structure of lanthanum ions interacting with chlorophyll-a of the fern Dicranopteris dichotoma grown in a rare earth minefield in southern China was determined by the extended x-ray absorption fine structure (EXAFS). The results show that lanthanum includes two porphyrin rings in its ...
The technique of x-ray absorption spectroscopy using tuneable, very intense x-rays from a high energy electron storage ring has been applied to study of the estended x-ray absorption fine structure for Cu and Ni tetraphenylporphyrin and methemoglobin. Preliminary analysis shows that the spectra may be interpreted ...
We investigate the effect of variation in the value of the fine-structure constant (alpha) at high redshifts (recombination > z > 30) on the absorption of the cosmic microwave background (CMB) at 21 cm hyperfine transition of the neutral atomic hydrogen. We find that the 21 cm signal is very sensitive to the variations in alpha and it is so far the ...
Extended x-ray absorption fine structure (EXAFS) has been developed to determine the structure of metalloproteins. EXAFS data have been collected and analysed for four states in the catalytic cycle of bacterial cytochrome P-450/sub CAM/. This data demonst...
A number of copper proteins have been investigated using the EXAFS and XANES techniques. Some of the work is reviewed here to demonstrate the contribution of these techniques in specific structure determination. The author also reports here some of the re...
This paper reports the X-ray absorption near edge structure (XANES) spectroscopic characterization of the oxidation state of selenium following microbial metabolism of selenite from aqueous solution. Extended X-ray absorption fine structure (EXAFS) measurements of the amorphous red and gray ...
A critical review about the existing theories of extended fine structure of the X-ray absorption spectra of polycrystalline and amorphous solids is given. The fine structure of the K-absorption has been calculated according to the HAYASI, SHIRAIWA and KOZLENKOV theory using ...
Extended x-ray absorption fine structure measurements were performed on trigonal tellurium (t-Te) and tellurium nanoparticles in very thin films. Twofold coordinated chains, much like those in t-Te, exist even in the nanoparticles, but covalent bonds or intrachain interactions are stronger than those of t-Te as shown by a shorter bond ...
Experiments were carried out in order to determine the direction and rats of changes taking place in the fine structure of x-ray absorption K spectra of iron in antiferromagnetics and ferrites and their relation to magnetic state changes of these materials. The antiferromagnetic modification of iron oxide ( alpha -Fe/sub ...
Zinc metallothionein-1 from rabbit liver has been investigated by means of Zn K-edge extended x-ray absorption fine structure (e.x.a.f.s.). Also, the Cu and Zn K-edge e.x.a.f.s. have been measured for two samples of mixed Cu-Zn metallothionein-2, with Cu:...
Pressure-induced changes in the local structure about Rb atoms in RbCl are investigated by means of x-ray-absorption fine-structure spectroscopy. Rb K-edge data were taken in fine steps across the pressure-induced NaCl-structure (B1)-to-CsCl-structure(B2)transition at 0.55 ...
We have constructed an x-ray monochromator based on a log spiral of revolution covered with highly oriented pyrolytic graphite. Such a monochromator is used for obtaining x-ray absorption edge fine structure by the fluorescence method, and is particularly useful for measuring the fine structure ...
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 ...
We use the relativistic Hartree-Fock method, many-body perturbation theory, and configuration-interaction method to calculate the dependence of atomic transition frequencies on the fine-structure constant {alpha}=e{sup 2}/({Dirac_h}/2{pi})c. The results of these calculations will be used in the search for variation of the fine-structure constant in quasar ...
Additional data are given on titanium absorption K spectra in Ti-C systems with carbon contents of 12 to 24 wt.%. Diagraras are presented of the x- ray K spectra and K beta /sub 5/ line of titmium emission in carbides with various carbon contents and of the juxiaposition of x-ray K spectra for titanium absorption in carbide and rutile. (R.V.J.)
The extended x-ray absorption fine structures (EXAFS) associated with the L/sub III/ absorption edge of iridium and the K absorption edge of rhodium were investigated for catalysts containing bimetallic clusters of these elements dispersed on silica or alumina. The catalysts contained 1 wt.% ...
New concepts for time-resolved x-ray absorption spectroscopy using the quick-extended x-ray absorption fine structure (QEXAFS) method are presented. QEXAFS is a powerful tool to gain structural information about, e.g., fast chemical reactions or phase transitions on a subsecond scale. This can ...
A method for surface structure analysis is proposed. The proposed process combines x-ray photoabsorption and Auger electron emission. The extended x-ray-absorption fine structure, occurring for photon energies above an atomic absorption edge, contains structural information ...
The technique of SEXAFS (Surface Extended X-ray Absorption Fine Structure) has been developed to the stage where adsorbate-substrate distances can be determined to within 0.02 A, and adsorption sites readily deduced for single crystal surfaces. Several examples of adsorption on semiconductors (Te, I on Si(111), Ge(111) and Pd, Ag on ...
... Title : THE FINE STRUCTURE OF THE HYDROGEN ALPHA LINE AND THE STRUCTURE OF THE SPECTRAL LINES OF HEAVY ATOMS. ...
