Grazing-incidence XAFS studies

Grazing-Incidence XAFS Studies of Co(II) and Pb(II) Sorption on Single Crystal a-Al203 and Ti02... 

Towle SN, Bargar JR, Brown GE Jr, Parks GA (1999b) Sorption of Co(II) on metal oxide surfaces II. Identification of Co(II)(aq) adsorption sites on (1-102) and (0001) surfaces of a-Al203 by grazing-incidence XAFS spectroscopy. J Colloid Interface Sci 217 312-321 Trainor TP (2001) X-ray Scattering and X-ray Absorption Spectroscopy Studies of the Structure and Reactivity of Aluminum Oxide Surfaces. Ph.D. Dissertation. Department of Geological Environmental Sciences, Stanford University, Stanford, CA, USA Trainor TP, Brown GE Jr, Parks GA (2000) Adsorption and precipitation of aqueous Zn(II) on alumina powders. J Colloid. Interface Sci 231 359-372... 

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. 

The surface study was performed at BL-7C of the same facility by the total-reflection XAFS(TR-XAFS) method. The experiments were done at 1 mrad grazing incidence angle, since at the Br K-edge energy, the critical angle for the total-reflection is about 2 mrad at the water surface. In order to reduce the X-ray absorption by air and water vapor, the solution surface was covered by helium gas. 

Systems with lower concentrations of heavy metal ions can be studied by means of gra2ing-incidence XAFS spectroscopy. In grazing-incidence geometry the X-ray beam penetrates only about 10 nm into the sample. This method can be applied to study sorption on specified crystallographic planes when single crystals are used rather than powders. Incident beam angles of a fraction of E assure total (external) reflection geometry. 

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