X-ray absorption spectroscopy applications

Pfalzer P, Urbach JP, Klemm M, Horn S, denBoer ML, Frenkel AI, Kirkland JP (1999) Ehmination of selfabsorption in fluorescence hard-X-ray absorption spectra. Phys Re B60 9335-9339 Powers L (1982) X-ray absorption spectroscopy. Application to biological molecules. Biochim Biophys Acta 638 1-38... 

X-Ray Absorption Spectroscopy Applications of Electrospray Mass Spectrometry Other Techniques... 

XAS (X-ray absorption spectroscopy) applications, 24 disadvantages, 4 peculiarity, 24 physical principles, 2 sites of impurities, determination of, 24 spectrum, 22 theory, 2... 

EXAFS is part of the field of X-ray absorption spectroscopy (XAS), in which a number of acronyms abound. An X-ray absorption spectrum contains EXAFS data as well as the X-ray absorption near-edge structure, XANES (alternatively called the near-edge X-ray absorption fine structure, NEXAFS). The combination of XANES (NEXAFS) and EXAFS is commonly referred to as X-ray absorption fine structure, or XAFS. In applications of EXAFS to surface science, the acronym SEXAFS, for surface-EXAFS, is used. The principles and analysis of EXAFS and SEXAFS are the same. See the article following this one for a discussion of SEXAFS and NEXAFS. 

Applications ofSynchrotron Radiation. (H. Wmick, D. Xian, M. H. Ye, and T. Huang, eds.) Gordon and Breach, New York, 1988, Volume 4. F. W. Lytle provides (pp. 135—223) an excellent tutorial survey of experimental X-ray absorption spectroscopy. 

X-ray absorption spectroscopy a new structural method and its applications to bioinorganic chemistry. S. P. Kramer and K, O. Hodgson, Prog, Inorg. Chem., 1979, 25,1-39 (71). 

Transition metal oxides, rare earth oxides and various metal complexes deposited on their surface are typical phases of DeNO catalysts that lead to redox properties. For each of these phases, complementary tools exist for a proper characterization of the metal coordination number, oxidation state or nuclearity. Among all the techniques such as EPR [80], UV-vis [81] and IR, Raman, transmission electron microscopy (TEM), X-ray absorption spectroscopy (XAS) and NMR, recently reviewed [82] for their application in the study of supported molecular metal complexes, Raman and IR spectroscopies are the only ones we will focus on. The major advantages offered by these spectroscopic techniques are that (1) they can detect XRD inactive amorphous surface metal oxide phases as well as crystalline nanophases and (2) they are able to collect information under various environmental conditions [83], We will describe their contributions to the study of both the support (oxide) and the deposited phase (metal complex). 

The applications of polarized x-ray absorption spectroscopy (PXAS) for structure determination in inorganic and bioinorganic systems are discussed. PXAS studies of oriented samples add angular detail to the information obtained from x-ray absorption edges and from EXAFS. In some cases, PXAS can be used to determine molecular orientation. In other cases, PXAS can be used to infer the details of electronic structure or of chemical bonding. Some of the potential future applications of PXAS are discussed. 

In this chapter, we briefly discuss the theoretical background of polarized x-ray absorption spectroscopy (PXAS). Many of the recent applications of synchrotron radiation to polarized absorption edge structure and to EXAFS are discussed, with particular emphasis being given to the study of discrete molecular systems. We present here some indication of the potential applications of PXAS to systems of chemical and biological interest. 

Cramer, Stephen P. and Hodgson, Keith O., X-Ray Absorption Spectroscopy A New Structural Method and Its Applications to Bioinorganic Chemistry. .. 25 1... 

Now X-ray region has been opened to the photoacoustic spectroscopy. However, as seen in this text, the photoacoustic X-ray absorption spectroscopy is still in primitive stage. For the real applications, it seems that the sensitivity should be improved at least 10 times better than now or the photon flux should be increased by focusing or insertion devices. With the specific character of X-ray absorption, e.g. transparency of X-ray and abrupt edge shape absorption profile, this method seems to have hopeful future when the unique photoacoustic application can be conducted. 

Hayes, K. F. Katz, L. E. 1996. Application of X-ray absorption spectroscopy for surface complexation modelling of metal ion sorption. In Brady, P. V. (ed) Physics and Chemistry of Mineral Surfaces. CRC Press, Boca Raton, 147-223. 

Some of the potential benefits of X-ray absorption techniques in studies of catalysts were pointed out in a pioneering article by Van Nordstrand (2), but widespread application of X-ray absorption spectroscopy first began only after Sayers, Stern, and Lytle (5) had provided a theoretical under-... 

Figure 4.3 Reprinted from Wear, Vol. 202, Z. Yin, M. Kasrai, M. Fuller, G.M. Bancroft, K. Fyfe and K.H. Tan, Application of soft X-ray absorption spectroscopy in chemical characterization of anti wear films generated by ZDDP the effect of physical parameters, Part I, pp. 172-191. Copyright 1997, with permission from Elsevier.

XAS, and particularly its application to catalysis, has been the subject of several previous reviews and books. In 1988, Koningsberger and Prins published the book "X-ray absorption principles, applications, techniques of EXAFS, SEXAFS and XANES" (Koningsberger and Prins, 1988). In this monograph there is a thorough description of the technique together with a chapter on its application to catalysis. Iwasawa in 1996 published "XAFS for catalysts and surfaces" (Iwasawa, 1996), which focused solely on XAFS spectroscopy as applied to catalyst characterization. This volume includes a chapter by Bazin, Dexpert, and Lynch about measurements of catalysts in reactive atmospheres, and several other chapters allude to examples of such characterization. Recently a book entitled In situ Spectroscopy of Catalysts" (Weckhuysen, 2004) was published that contains three chapters focused on XAFS of catalysts in reactive atmospheres one on XANES, one on EXAFS, and one on time-resolved XAFS. 

XANES — X-ray absorption near-edge structure an application of X-ray absorption spectroscopy where the fine structure of the absorption edge displayed in an X-ray absorption spectrum around and slightly below the absorption edge is analyzed, for details see -> surface analytical methods. 

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