Directory on numerical X-ray absorption near edge structure (XANES) studies

Early Stages of Copper Electrocrystallization: Electrochemical and in Situ X-ray Absorption Fine Structure Studies of Coadsorption of Copper and Chloride at the Au(111) Electrode Surface

“…The spectra for the model compounds agree well with the spectra published in the literature (Cu , , Cu 2 O, and CuCl). There is general agreement that the edge signal for metallic copper arises from 4p ← 1s dipole-coupled transitions. − The intensity of this transition is described by where Ψ f and Ψ i are the final and initial state wave functions, e is the vector which represents the direction of the polarized radiation, r is the transition dipole operator, ϑ is the angle between e and r , and N ( E ) is the projected density of states. The shape of the copper edge is essentially determined by the empty 4p band structure, that is, by the term N(E) in eq 6 …”

“…The X-ray absorption spectra are discussed in several parts; first we discuss the near edge region which corresponds roughly to the first 8−10 eV; then we qualitatively examine the extended fine structure, followed by an analysis of the extended XANES region 10−50 eV beyond the edge, using FEFF 6.01 calculations. There is a general consensus that the shape of the near edge region is best described in terms of electronic transitions to bound and quasi-bound states, while the XANES structure is best described as arising from multiple scattering of the photoelectron by neighboring atoms, in some cases out to distances of more than 5 Å. − In our discussion of the near edge features we propose a qualitative interpretation, based on comparison to spectra of model systems. After our qualitative discussion of the extended fine structure (section 3.2.2), we report in section 3.2.3 our attempts to find a quantitative interpretation of both XANES and extended X-ray absorption fine structure (EXAFS) by comparison to spectra calculated for a number of trial geometries using the FEFF 6.01 polarization dependent multiple scattering theory of Rehr et al , …”

“…There is a general consensus that the shape of the near edge region is best described in terms of electronic transitions to bound and quasi-bound states, while the XANES structure is best described as arising from multiple scattering of the photoelectron by neighboring atoms, in some cases out to distances of more than 5 Å. [50][51][52] In our discussion of the near edge features we propose a qualitative interpretation, based on comparison to spectra of model systems. After our qualitative discussion of the extended fine structure (section 3.2.2), we report in section 3.2.3 our attempts to find a quantitative interpretation of both XANES and extended X-ray absorption fine structure (EXAFS) by comparison to spectra calculated for a number of trial geometries using the FEFF 6.01 polarization dependent multiple scattering theory of Rehr et al 48,49 In a few recent papers, the near edge spectra of Cu electrodeposited on gold 8,10 or Pt 14 electrode surfaces were compared to the spectra of model copper compounds and the similarity between the edge position and shape for the electrodeposited copper and a model compound was used to estimate the oxidation state of copper adatoms.…”

X-ray absorption spectroscopy: state-of-the-art analysis

“…The current status of techniques for calculating the inner-shell photoabsorption cross section for clusters, based on the real-space MS method and using the local density approximation for exchange and correlation, has been reviewed by many authors. A theoretical review mainly focused on EXAFS and to a lesser extent on XANES with emphasis on the path-by-path method has been given by Rehr & Albers (2000), whereas XANES analysis has been treated in the reviews by Kizler (1993), Binsted & Hasnain (1996), Ankudinov (1999) and, in the special case of narrow-band highly correlated materials, de Groot (1996). In particular, Binsted & Hasnain (1996) have advocated the ®tting of the entire XAS spectrum rather than its components, EXAFS and XANES, and have reached the conclusion that this is a viable procedure.…”

Improvements in Controllability of Ultrasonic Linear Motors by Longitudinal-Bending Multilayered Transducers with Independent Electrodes

“…Beaurepaire et al [9] made a comparison between the Bremsstrahlung isochromat spectroscopy (BIS) and XAS absorption for TiO 2 . Several authors compared different methods of calculation, for example, Kizler [10] discusses augmented plane wave (APW), linear muffin-tin orbital (LMTO) and multiple scattering (MS) methods to calculate the K-or L-edges of many systems and draws conclusions about their efficiency. De Groot et al [11], Zaldo et al [2] and Poumellec et al [12] calculated the titanium dioxide density of states (DOS) for rutile or anatase.…”