Spectroscopy XANES

Nagy, L. Theoretical Background ofEXAFS and XANES Spectroscopies. Application in Inorganic and in Bioinorganic Chemistry. Novel Results in Chemistry, Akademiai Kiado, Budapest, 1999 p. 63. 

Abstract Molecular spectroscopy is one of the most important means to characterize the various species in solid, hquid and gaseous elemental sulfur. In this chapter the vibrational, UV-Vis and mass spectra of sulfur molecules with between 2 and 20 atoms are critically reviewed together with the spectra of liquid sulfur and of solid allotropes including polymeric and high-pressure phases. In particular, low temperature Raman spectroscopy is a suitable technique to identify single species in mixtures. In mass spectra cluster cations with up to 56 atoms have been observed but fragmentation processes cause serious difficulties. The UV-Vis spectra of S4 are reassigned. The modern XANES spectroscopy has just started to be applied to sulfur allotropes and other sulfur compounds. 

X-ray absorption near edge structure (XANES) spectroscopy is a non-destructive and sensitive probe of the coordination number and geometry as well as of the effective charge of a chosen atom within a molecule and therefore also of the formal oxidation number. Recently, there have been a number of XANES studies at the sulfur K-edge demonstrating the sensitivity of... 

Thus, XANES spectroscopy of elemental sulfur has mainly be used to detect the particular sulfur species in samples not accessible to other spectroscopic methods, e.g., in cultures of sulfur bacteria [215, 221, 222, 224]. However, the main application is in the area of sulfur compounds with other elements. For a recent review, see [226]. 

Ressler T, J Wong, J Roos, IL Smith (2000) Quantitative speciation of Mn-bearing particulates emitted from autos burning (methylcyclopentadienyl)manganese tricarbonyl-added gasolines using XANES spectroscopy. Environ Sci Technol 34 950-958. 

XANES spectroscopy shows that a narrow and intense pre-edge peak at 4967 eV, due to the Is 3pd electronic transition involving Ti atoms in tetrahedral coordination, is present in well-manufactured TS-1 (Fig. 2c). Conversely this electronic transition of Ti(IV) species in Ti02 (anatase or rutile) is characterized by a very low intensity due to the small pd hybridization in octahedral symmetry. Indeed the transitions l2g are symmetrically forbidden in the case of octahedral coordination of Ti (IV), but the transition Ai T2 is allowed in the case of tetrahedral coordination of Ti(IV), as in the case of [Ti04] units [52,58-61,63,68]. 

Kim et al. (19) also observed that the ee of recovered epichlorohydrin was reduced to 17% in the second hydrolysis reaction with Jacobsen s Co-OAc salen catalyst, if the catalyst was not regenerated with acetic acid in air. Although they attributed the loss of enantioselectivity to the reduction of Co(lll) to Co(ll) salen complex after the HKR reaction, no spectroscopic evidence was provided. Therefore, we probed the catalyst by UV-Vis and XANES spectroscopy before and after the HKR reaction. 

XANES spectroscopy is also the basis of chemically sensitive X-ray imaging, as well as qualitative and quantitative microspectroscopy [306], ptXANES is attractive for chemical analysis, with its spatial resolution down to 10 ptm. Variations on the theme are surface EXAFS (SEXAFS), grazing incidence XAS and in situ time-resolved XAS investigations. Grazing angle XAFS can be used for the study of ultrathin multilayer systems. 

Fine-Structure (EXAFS) and X-ray Absorption Near-Edge (XANES) Spectroscopies.122... 

X-ray absorption near-edge structure (XANES) spectroscopy,... 

Boye K, Almkvist G, Nilsson SI, Eriksen J, Persson I. Quantification of chemical sulphur species in bulk soil and organic sulphur fractions by S K-edge XANES spectroscopy. Eur. J. Soil Sci. 2011 62 874-881. 

A Sulfur K Edge X-ray Absorption Near Edge Structure (XANES) Spectroscopy method has been developed for the direct determination and quantification of the forms of organically bound sulfur in nonvolatile petroleum and coal samples. XANES spectra were taken of a number of model compounds, mixtures of model compounds, heavy petroleum and coal samples. Analysis of the third derivatives of these spectra allowed approximate quantification of the sulfidic and thiophenic components of the model mixtures and of heavy petroleum and coal samples. These results are compared with those obtained by X-ray Photoelectron Spectroscopy (XPS). 

Mitra-Kirtley, S., Mullins, O. C., Branthauer, J. F., and Cramer, S. P. (1993). Determination of the nitrogen chemical structures in petroleum asphaltenes using XANES spectroscopy. J. Am. Chem. Soc. 115, 252-258. 

Vairavamurthy, A., and Wang, S. (2002). Organic nitrogen in geomacromolecules insights on speciation and transformation with K-edge XANES spectroscopy. Environ. Sci. Technol. 36,3050-3056. 

It must be emphasized that these marker signals can be used exclusively for the interpretation of Py-FI mass spectra, but not for the interpretation of conventional Cp Py-GC/MS because of the completely different heating and ionization conditions. The interpretation of the routine Py-FI mass spectra will be incrementally improved by the application of complementary techniques such as high-resolution Py-FIMS with a MAT 900 (see below) and synchrotron-based X-ray absorption near edge structure (XANES) spectroscopy (Section 14.3.2). 

Jokic, A., Cutler, J. N., Anderson, D. W., and Walley, E (2004b). Detection of heterocyclic N compounds in whole soils using N-XANES spectroscopy. Can. J. Soil Sci. 84,291-293. 

Ade, H., Zhang, X., Cameron, S., Costello, C., Kirz, J., and Williams, S. (1992). Chemical contrast in X-ray microscopy and spatially resolved XANES spectroscopy of organic specimens. Science 258, 972-975. 

Boese, J., Osanna, A., Jacobsen, C., and Kirz J. (1997). Carbon edge XANES spectroscopy of amino acids and peptides. J. Electr. Spectr. Rel. Phen. 85, 9-15. 

Morra, M. J., Fendorf, S. E., and Brown, P. D. (1997). Speciation of S in humic and fulvic acids using X-ray absorbtion near-edge structure (XANES) spectroscopy. Geochim. Cosmochim. Acta 61, 683-688. 

Sato, S., Solomon, D., Hyland, C., Ketterings, Q. M., and Lehmann, J. (2005). Phosphorus speciation in manure and manure-amended soils using XANES spectroscopy. Environ. Sci. Technol. 39,7485-7491. 

Schulze, D. G., McCay-Buis, T., Sutton, S. R., and Huber, D. H. (1995). Manganese oxidation states in Gaeumannomyces-infested wheat rhizospheres probed by micro-XANES spectroscopy. Phytopathology 85, 990-994. 

Shober, A. L., Hesterberg, D. L., Sims, J.T., and Gardner, S. (2006). Characterization of phosphorus species in biosolids and manures using XANES spectroscopy. /. Environ. Qual. 35, 1983-1993. 

Solomon, D., Lehmann, J., and Martinez, C. E. (2003). Sulfur K-edge XANES spectroscopy as a tool for understanding sulfur dynamics in soil organic matter. Soil Sci. Soc. Am. J. 67, 1721-1731. 

Zhao, F. I, Lehmann, I, Solomon, D., Fox, M. A., and McGrath, S. P. (2006). Sulphur specia-tion and turnover in soils evidence from sulphur K-edge XANES spectroscopy and isotope dilution studies. Soil Biol. Biochem. 38,1000-1007. 

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