K absorption edges

Wavelength shift of K absorption edge of sulfur, 37, 38 Weight-fraction , use, 164, 171 Window absorption, 45 Windowless counter tube, 55, 222 Windows, for electron beam, 177 for proportional counter, 55... 

Herman Pines and Luke A. Schaap The Use of X-Ray K-Absorption Edges in the Study of Catalytically Active Solids Robert A. Van Nordstrand The Electron Theory of Catalysis on Semiconductors Th. Wolkenstein... 

Figure 1. X-ray absorption spectrum of a silica supported ruthenium-copper catalyst at 100 K In the vicinity of the K absorption edge of ruthenium. Reproduced with permission from Ref. 8. Copyright 1980, American Institute of Physics.

K Absorption Edges of Potassium and Chlorine in Various Compounds, ... 

Electronic Structure Determination, Cox and Beaumont have studied the polarized x-ray absorption edge of a single crystal of Zn 2 (23), in which the Zn has tetragonal (D ) site symmetry. The observed anisotropic K-absorption edges were explained in terms of a ls+4p and a ls-K4p, 4p ) transition. 

Figure 5.4 X-ray tube output spectrum, showing continuous emission and line spectra of the target material (in this case gold). The K absorption edges for major elements in silicate glasses are shown below the diagram, indicating that the gold M lines are particularly effective for the analysis of the light elements Na to P.

K-absorption edges in study of, 12 149 structure of, and magnetism, 3 27 Catalytic behaviors, metallic oxides, 29 240 Catalytic converter automotive, 24 71, 72 single-bed, 24 72, 74 design of, 24 75-77, 83-86 dual-bed, 24 73... 

Position assessed by method of Iwata, et al., reference 83. Mobility assessed by comparisons of anomalous Fe peak heights data collected at or near the iron K absorption edge. (See references 84 and 88.) ... 

The effects of an absorption edge are shown in an important case for semiconductors in Figure 4.4. This shows the real and imaginary parts of the scattering factors for gallium and arsenic near the K absorption edges. The exchanges in values, and resultant intensities, that are shown can and have been used for composition- sensitive experiments such as the determination of stoichiometry in III-V semiconductors. However, the tunabihty of a synchrotron radiation source is required for such experiments in most cases. 

Figure 4.4 The real (scattering) and imaginary (absorption) parts of the atomic scattering factor for gallium and arsenic near the K absorption edges. After Cockerton etal. ...

The Use of X-Ray K-Absorption Edges in the Study of Catalytically Active Solids... 

K EDGE ABSORPTION SPEGTRA. The absorption of x-rays in the vicinity of the K absorption edge of transition metals gives information on both oxidation state and coordination geometry of the central absorbing atom. The energy positions of various absorption features have been demonstrated to be correlated to the formal valence of V in an extensive series of oxides, vanadates and intermetallics (13"). 

Figure 8.1 Theoretically calculated f and f" values as a function of wavelength in the vicinity of the K absorption edge of selenium (a) and the L edge of holmium (b).

Takakura, K. Auger effects on bromo-deoxyuridine-monophosphate irradiated with monochromatic X-rays around bromine K-absorption edge. Radiat. Environ. Biophys. 1989, 28 (3), 177-184. 

Maezawa, H. Hieda, K. Kobayashi, K. Furusawa, Y. Mori, T. Suzuki, K. Ito, T. Effects of monoenergetic X-rays with resonance energy of bromine K-absorption edge on bro-mouracil-labelled E. coli cells. Int. J. Radiat. Biol. Relat. Stud. Phys. Chem. Med. 1988, 53 (2), 301-308. 

Traditionally, X-ray absorption edge measurements have been used to determine oxidation states of metals in complex materials. The extended X-ray absorption fine structure (EXAFS), on the other hand, provides structural information such as bond distances and coordination numbers even with powdered samples, crystalline or amorphous, the fine structure essentially resulting from short-range order around the absorbing atom. The technique is also useful for studying solid surfaces (SEXAFS). The observation of fine structure beyond the K-absorption edges of materials dates back to... 

Fig. 221. Anomalous scattering of X-rays of wavelength near that of an absorption edge. Iron atom,. K absorption edge, a. Definitions4 6, o and d. A/, A/, and 4 in relation to A/Ajp (the ratio of incident wavelength to that. of the K absorption edge of the iron atom).

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