X-ray Absorption Fine Structure Combined with X-ray Fluorescence Spectrometry. Improvement of Spectral Resolution at the Absorption Edges of 9−29 keV

Abstract

X-ray absorption near-edge structure (XANES) suffers from core-hole lifetime broadening at a higher energy absorption edge, such as Sn K (29 keV, Gamma(K) = 8.49 eV). To overcome this problem, emitted Sn Kalpha1 fluorescence from sample was counted using high-energy-resolution fluorescence spectrometer in the XANES measurements. Experimental energy resolution (5.0 eV) was consistent with theoretical values based on the Rowland configuration of the spectrometer. The absorption edge became steeper compared to conventional spectra. The white-line peak due to Sn(II) species became remarkably sharper and more intense in the Sn Kalpha1-detecting Sn K-edge XANES for Pt-Sn/SiO2. To support the semiclassical theory of resonant Raman scattering for the explanation of observed elimination of lifetime width, more resolved XANES data at Cu K, Pb L3, and Sn K in this work were convoluted (filtered) with a Lorentzian of each core-hole lifetime width. The processed data resembled generally well corresponding XANES spectrum measured in transmission mode. The verification based on ab initio XANES calculations was also performed.

On the local coordination of Fe in Fe2O3-glass and Fe2O3-glass ceramic systems containing Pb, Na and Si

“…The pre-peak of the Pb-containing sample (name prefix PF) and the reference samples are shown in Fig. 5(a), those from the hematite-soda binary (FN) and the ternaries with 50 wt% lifetime [18]). The results of the NEXAFS analysis and the assignment of the various peaks to the different coordination geometries of the Fe ion are listed in Table 3.…”

Synthesis and Site Structure of a Replica Platinum−Carbon Composite Formed Utilizing Ordered Mesopores of Aluminum-MCM-41 for Catalysis in Fuel Cells

“…Spectrum (b) seemed to be a mixture of metallic Pt and Pt at the interface with C. Instead, Pt L 1 -selecting XANES spectra were compared to theoretical data because the Pt state was selected and the spectral pattern was sharpened. 28,29,[42][43][44][45][46][47] The XANES spectrum for the replica Pt-C composite in air is shown in Figure 3c. The energy of first peak above the absorption edge (11566.7 eV) is intermediate between the peak at 11565.6 eV for the Pt metal (spectrum (e)) and the one at 11567.3 eV for PtO 2 (spectrum (f)).…”

Specific Oxidative Dehydrogenation Reaction Mechanism over Vanadium(IV/III) Sites in TiO2 with Uniform Mesopores under Visible Light

“…First, the V K 5;2 -selecting XANES spectrum for fresh sample was compared to that measured in transmission mode (Figures 4a and 4b). The enhanced peak feature at 5486 and 5504 eV for spectrum-a was due to a resonance excitation effect reported for Fe K 1;3 -selecting, 25 Cu K 1 -selecting, 21 Sn K 1 -selecting, 21 and Pb L 1 -selecting XANES spectra. 21 With the introduction of 0.37 kPa of water, the vanadium K absorption edge shifted by 0.5 eV toward lower energy (Figure 4c), consistent with the negative energy shift of the V K 5;2 main peak ( Figures 3a and 3b and Table 2A).…”

“…The X-ray fluorescence emitted from samples was analyzed with a homemade fluorescence spectrometer. 18,19,21,22 A slit 0 was set in front of an ion chamber (S1194-B1, Oken) for the I 0 signal count. The ion chamber was purged with a mixture of helium and nitrogen (7:3).…”