Synchrotron X-ray analysis

Figure I. Schematic illustrations of microfocus synchrotron X-ray analysis methods (a) small-angle X-ray scattering (SAXS) (b) microfocus X-ray diffraction (XRD) and (c) microfocus X-ray fluorescence (XRF).

O Toole NJ, Streltsov VA (2001) Synchrotron X-ray analysis of the electron density in C0F2 and ZnF2. Acta Cryst 857 128-135... 

Janssens, K., Aerts, A., Yincze, L., et al. (1996). Corrosion phenomena in electron, proton and synchrotron X-ray microprobe analysis of Roman glass from Qumran, Jordan. Nuclear Instruments and Methods B 109-110 690-695. 

Dhavan, G.M. Chance, M.R. Brenowitz, M. Kinetics analysis of DNA-protein interactions by time-resolved synchrotron X-ray footprinting. Kinet. Anal. Macromol. 2003, 75-86. 

The five room-temperature and two liquid-nitrogen temperature data sets obtained in these experiments were reanalyzed by Cummings and Hart (1988). Where necessary, they introduced improved corrections for residual strain, resonance, and nuclear scattering to arrive at a set of mean structure-factor values with typical errors of 3-5 millielectrons. This is extremely good, but as noted, for some reflections the errors are significantly larger than the 0.1% claimed earlier. Additional accurate values for individual reflections are available for y-ray (Alkire et al. 1982), X-ray (Roberto and Batterman 1970, Trucano and Batterman 1972), and synchrotron X-ray (Tischler 1983, Tischler and Batterman 1984), measurements. Combined, these measurements provide a superbly accurate set for analysis of the charge density in silicon. 

For the future, even smaller-scale sample areas can be considered for analysis as can isotope ratios. It could be envisaged that multiscale prospection analyses could proceed from optical methods to microfocus synchrotron X-ray fluorescence and SAXS and, finally, to destructive isotopic studies with LA-ICP-MS or to finer resolutions with SIMS. 

Possible explanations for this unusual behaviour have been offered by first-principles band structure calculations and synchrotron X-ray structural studies. The former revealed that, because of hybridisation between Ba and C orbitals, the rigid-band model is not appropriate for the description of the electronic properties and the calculated N(ev) for K3Ba3C60 and Rb3Ba3C60 are almost identical [69]. The structural analysis revealed positional disorder of the Ba2+ and K+ ions in the distorted tetrahedral sites of the bcc structure and the existence of short Ba-C and K-C contacts, consistent with strong hybridisation between the K, Ba and the C60 states [70]. It is important to notice that in K3Ba3C60 there is a perfect matching between the size of K+ and Ba2+ ions, while in both the Rb+ and Cs+ analogues, there is a considerable mismatch, which leads to fundamental structural... 

P. Anderson, S.E.P. Dowker, J.C. Elliott, C.R. Thomas, Synchrotron X-ray fluorescence microprobe analysis in the study of dental mineralized tissues, J. Trace Microprobe Tech. 14 (3) (1996) 541-560. 

It has been reported based on the analysis of synchrotron X-ray powder diffraction data that the electronic distribution around the O atom is elongated in the directions perpendicular to the Ti-O covalent bond in SrTi03, but not in BaTi03 or PbTi03 [8]. Such a result may be associated with the present finding that the Ba-O and Pb-O bonds involve covalent interactions with repulsive and... 

Kaplan, D.I. et al., Application of synchrotron x-ray fluorescence spectroscopy and energy dispersive x-ray analysis to identify contaminant metals on groundwater colloids, Environ. Sci. Technol., 28, 1186, 1994. 

From the analysis of the data in the LIPID AT database (41), more than 150 different methods and method modifications have been used to collect data related to the lipid phase transitions. Almost 90% of the data is accounted for by less than 10 methods. Differential scaiming calorimetry strongly dominates the field with two thirds of all phase transition records. From the other experimental techniques, various fluorescent methods account for 10% of the information records. X-ray diffraction, nuclear magnetic resonance (NMR), Raman spectroscopy, electron spin resonance (ESR), infrared (IR) spectroscopy, and polarizing microscopy each contribute to about or less than 2-3% of the phase transition data records in the database. Especially useful in gaining insight into the mechanism and kinetics of lipid phase transitions has been time-resolved synchrotron X-ray diffraction (62,78-81). 

Figure 27 Elemental abundances in matrix material in C03 chondrites normalized to bulk chondrite data for rims on chondrules in ALHA77307 (type 3.0) obtained by synchrotron X-ray fluorescence microprobe analysis (Brearley et aL, 1995) and for bulk matrix in Omans (type 3.3) analyzed by instrumental neutron activation (data from Rubin and Wasson, 1988). Chondrule rims in ALHA77307 are uniform in composition but deviate significantly from the bulk chondrite composition. Matrix in Ornans is relatively unfractionated (reproduced by permission of Elsevier from...

Winkler HGF (1948) Synthese und Kristallstruktur des Eukiyptits, LiAlSi04. Acta Ciystallogr 1 27-34 Xu H, Heaney PJ (1997) Memory effects of domain structures during displacive phase transitions a high-temperature TEM study of quartz and anorthite. Am Mineral 82 99-108 Xu H, Heaney PJ, Yates DM, Von Dreele RB, Bourke MA (1999a) Structural mechanisms underlying near-zero thermal expansion in p-eucryptite a combined synchrotron X-ray and neutron Rietveld analysis. J Mat Res 14 3138-3151... 

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