scispace - formally typeset
Search or ask a question
Topic

Extended X-ray absorption fine structure

About: Extended X-ray absorption fine structure is a research topic. Over the lifetime, 10452 publications have been published within this topic receiving 276744 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, a study of anisotropy effects in x-ray absorption in the layered compounds of layered compounds was presented, and the theoretical expression for the EXAFS anisotropic at the edges was explicitly displayed.
Abstract: A study is presented of anisotropy effects in x-ray absorption in the layered compounds of $2H\ensuremath{-}\mathrm{W}{\mathrm{Se}}_{2}$ and $1T\ensuremath{-}\mathrm{T}\mathrm{a}{\mathrm{S}}_{2}$. In the measurements it was essential to separate the thickness effect from the true anisotropy effect which is dependent on the angle between the x-ray polarization and the crystal axes. The Se $K$ edge and the W and Ta $L$ edges were measured. Anisotropy in the white line of Se was found but no anisotropy was discerned in the W and Ta white lines. It is pointed out that x-ray absorption in general, and the extended x-ray absorption fine structure (EXAFS) in particular, have the anisotropy dependence of a second-order tensor and the theoretical expression for the EXAFS anisotropy at the ${L}_{2,3}$ edges is explicitly displayed. The anisotropy of the EXAFS in the Se and W absorption was measured and a good agreement with theory is found. The anisotropy of EXAFS at the ${L}_{2,3}$ edges has the new feature of a cross term between the final $s$ and $d$ states, which permits a determination from the measurements that the average contributions of the final $s$ state is 0.02 of that of the final $d$ states to the total absorption of the W ${L}_{3}$ edge. Finally, only qualitative agreement is obtained between band calculations and the near edge x-ray absorption structure, as expected theoretically.

103 citations

Journal ArticleDOI
15 Sep 2000
TL;DR: The local structure of Cd(II) surface complexes adsorbed onto manganite (γ-MnOOH) has been investigated by extended X-ray absorption fine structure (EXAFS) spectroscopy as discussed by the authors.
Abstract: The local structure of Cd(II) surface complexes adsorbed onto manganite (γ-MnOOH) has been investigated by extended X-ray absorption fine structure (EXAFS) spectroscopy. Adsorption experiments were carried out within the pH range 7.4–9.8 and with surface coverage from 2.2 to 8.9 μmol/m2. Quantitative analysis of the EXAFS spectra shows little difference in the local coordination environment of Cd regardless of the coverage. Analysis of the first shell required a third cumulant in an asymmetric distribution model (i.e., non-Gaussian distribution), indicating distorted CdO6 octahedra with an average Cd–O distance of 2.31 A. A single second shell of Mn neighbors at a constant distance of 3.33 A was detected. This comparatively short distance shows that inner-sphere complexes are formed. No Cd neighbor was found which means that cadmium hydroxide precipitation or cluster formation does not occur at the surface at the experimental conditions probed in this study. We assign the Cd–Mn distance to edge sharing between CdO6 and MnO6 octahedra, with a geometry similar to that in the mixed solid Cd2Mn3O8. This adsorption mode is possible on the {110} and {010} cleavage planes of manganite.

103 citations

Journal ArticleDOI
TL;DR: X-ray absorption spectra have been measured using electron detection with both vacuum and helium gas surrounding the samples, and the extended x-ray-absorption fine-structure (EXAFS) amplitudes agree with transmission measurements to better than 3%.
Abstract: X-ray absorption spectra have been measured using electron detection with both vacuum and helium gas surrounding the samples. The samples consisted of thin iron films covered with various thicknesses of aluminum to determine the contribution versus depth. The height of the iron K--absorption-edge jump decreases exponentially with aluminum covering thickness, with a 1/e depth of 1600 A. The addition of helium gas forms an ionization detector for the electrons, which have an average energy of about 2500 eV. The effects of electrode geometry and bias voltage are evaluated. When operated in a linear-response region, the signal-to-noise ratio for this method is excellent and the extended x-ray-absorption fine-structure (EXAFS) amplitudes agree with transmission measurements to better than 3%.

103 citations


Network Information
Related Topics (5)
Raman spectroscopy
122.6K papers, 2.8M citations
90% related
Amorphous solid
117K papers, 2.2M citations
88% related
Oxide
213.4K papers, 3.6M citations
88% related
Thin film
275.5K papers, 4.5M citations
87% related
Graphene
144.5K papers, 4.9M citations
85% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023110
2022264
2021156
2020164
2019164
2018151