K-edge XANES spectra

Fig. 35 K-edge XANES spectra of solid 85, Sg, Sio, Sn, S14 and polymeric sulfur normalized at 2482 eV. Figure kindly provided by A. Prange [222]...

FIGURE 27.13 Cu K edge XANES spectra for a Cu full layer in sulfate solution at 0.2 V (SCE) in parallel (solid line) and perpendicular (dotted line) polarizations and for metallic copper (dashed line). (Erom Soldo et al., 2002, with permission from Elsevier.)... 

Fig. 16 P K-edge XANES spectra for CoP and C00.80V0.20P- The inset highlights the absorption edges, located by their inflection points (vertical dashed lines). Reprinted with permission from [60]. Copyright Elsevier...

Phosphorus 2p XPS and K-edge XANES Spectra Arsenic L-, K-edge XANES Spectra... 

This trend in metal charge can also be confirmed in the XANES spectra for the CrAsi-yPy and I eAsi VI series. The Cr K-edge XANES spectra in CrAsi vPv resemble the Mn spectrum seen earlier for MnP (Fig. 19), with the pre-edge peak... 

Figure 14.18. Difference thermograms showing changes in the volatilization of N-contaming compounds (- -) and peptides (-A-) in Py-FIMS (upper) and the corresponding difference N K-edge XANES spectra of samples taken at native and long-term cultivated sites along a climate gradient in Canada. Data for native soils minus data for cultivated soils.

Figure 1. Sulfur K-edge XANES spectra and formulae of selected model compounds illustrating the diversity of sulfur XANES spectra. All data have been normalized to the height of the edge jump. Because of the intensity of the spectrum of K2SO4 the vertical scale has been expanded by a factor of two.

Fig. 4.4. Phosphorus (P) K-edge XANES spectra of a thermo-oxidative tribofilm generated at 100°C (48-108 h heating time) for model compounds ZDDP, disulfide and Zn orthophosphate. The surface adsorbed species of the thermal film [B] is a rearranged ZDDP (linkage isomer, LI-ZDDP). A shoulder in the thermo-oxidative tribofilm indicates that there is some orthophosphate present (Fuller et al., 1998)...

The (S) L-edge XANES bulk (FY mode) spectra recorded were very weak, indicating that the film is thin (<10 nm), (Kasrai et al., 1998). The (S) K-edge XANES spectra of tribofilms along with neat MoDTC, MoS2 and Na2S04, recorded in the TEY (surface ) mode, are shown in Fig. 5.6. 

Fig. 1.1. Energy level diagram of the LUMO of a [Ti06]8 cluster with Oh, D2h(rutile) and D2d(anatase) symmetry in conjunction with (b) experimental K-edge XANES spectra.

Our aim of this study is to examine the chemical species and their ratios by analyzing A1 K-edge XANES spectra in the aqueous solution of aluminate when the structural transformation happens. The selected experimental XANES spectra in this study are of 23 min later (first-scan), 76 min later (transform-beginning), 85 min later (transform-end), and 103 min later (last-scan) in Figure 15.1, and are analyzed using the calculated curves derived from the discrete variational (DV)-Xx molecular-orbital (MO) calculations. 

Electron transition probabilities (hereafter ETPs) from the Is orbital of Al to the unoccupied orbitals are calculated from the SXS code [17] on the basis of the dipole approximation using electron state data of MOs. The theoretical Al K-edge XANES spectra of the models were obtained from convoluting a Gauss function to ETPs. 

In Table 15.2, the parameter of the energy shift is likely related with the structural difference between the structure model and actual structure. As described above, coordination number to Al ions, coordination of H20 molecules to Al ions, and interatomic distance between Al and O atoms usually affect the spectral shapes and the peak position of Al K-edge XANES spectra. The actual coordination structure of Al ions can be thus considered to be somewhat different in those points from the structure models used for the calculations. 

For understanding the structural transition from aqueous aluminate to crystalline Al(OH)3, curve fits for A1 K-edge XANES spectra have been performed using calculated curves and theoretical continuum curves. Coordination number to A1... 

FIGURE 47 Cobalt K-edge XANES spectra recorded during prereduction in H2 and SWNT synthesis at 1023 K and 6 bar of CO pressure (Ciuparu et at, 2005). Reprinted with permission from (Ciuparu et at, 2005). Copyright 2005 American Chemical Society. 

Fjo. 8. Oxidation state versus energy positions of various absorption features in the V K edge XANES spectra of various vanadium oxides. From Wong era/. (3/2). 

Knapp et al. (144) show that for oxides containing 3d elements in spinel, perovskite, rocksalt, or zircon-type structures, the K-edge XANES spectra are quite independent of 3d electron occupation but instead nicely correlate with the crystal structure type. Various studies of Ti K edges of titanium oxides and other titanium compounds have been reported (40,158,172,177, 297). 

Fig. 25. V K-edge XANES spectra of a Vj05-Ti02 catalyst (-), Mn, -1V2 2xMo2jt06...

Figure 7.39. XAFS CASE STUDY surface characterization of dispersed CuO catalysts on silica and alumina/silica supports. Shown are (A) EXAFS of the Cu K-edge of the catalyst calcined in air at 543 K. The thick and thin lines indicate Si/Al and Si supports, respectively (B) EXAFS of the Cu K-edge of the catalyst reduced under a H2 flow at 543 K (C) Cu K-edge XANES spectra of the calcined catalyst on (a) Si02, (b) Si02/Al203 supports, along with references of (c) Cu foil, (d) CU2O, and (e) CuO (D) XPS spectrum of the Cu 2p core level of the calcined catalyst on a Si support (E) XPS spectrum of the catalyst on a Si/Al support. Reproduced with permission from Gervasini, A. ManzoU, M. Martra, G. Ponti, A. Ravasio, N. Sordelli, L. Zaccheria, F. J. Phys. Chem. B 2006,110, 7851.

---