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Metal K-edge spectroscopy is a spectroscopic technique used to study the electronic structures of transition metal atoms and complexes.This method measures X-ray absorption caused by the excitation of a 1s electron to valence bound states localized on the metal, which creates a characteristic absorption peak called the K-edge.
The edges are, in part, named by which core electron is excited: the principal quantum numbers n = 1, 2, and 3, correspond to the K-, L-, and M-edges, respectively. [4] For instance, excitation of a 1s electron occurs at the K-edge, while excitation of a 2s or 2p electron occurs at an L-edge (Figure 1).
In a more formal definition, the L shell is initially fully occupied. In this case, the lighter species with K-alpha is neon. [5] This choice also places K-alpha firmly in the X-ray energy range. Similarly to Lyman-alpha, the K-alpha emission is composed of two spectral lines, K-alpha 1 (Kα 1) and K-alpha 2 (Kα 2). [6]
This results in an absorption edge. Every element has a set of unique absorption edges corresponding to different binding energies of its electrons, giving XAS element selectivity. XAS spectra are most often collected at synchrotrons because the high intensity of synchrotron X-ray sources allows the concentration of the absorbing element to ...
The XANES energy region [3] extends between the edge region and the EXAFS region over a 50-100 eV energy range around the core level x-ray absorption threshold. Before 1980 the XANES region was wrongly assigned to different final states: a) unoccupied total density of states, or b) unoccupied molecular orbitals (kossel structure) or c) unoccupied atomic orbitals or d) low energy EXAFS ...
In physics, an absorption edge (also known as an absorption discontinuity or absorption limit) is a sharp discontinuity in the absorption spectrum of a substance. These discontinuities occur at wavelengths where the energy of an absorbed photon corresponds to an electronic transition or ionization potential .
For example, if aluminum K-alpha X-rays are used, the intrinsic energy band has a FWHM of 0.43 eV, centered on 1,486.7 eV (E/ΔE = 3,457). If magnesium K-alpha X-rays are used, the intrinsic energy band has a FWHM of 0.36 eV, centered on 1,253.7 eV (E/ΔE = 3,483). These are the intrinsic X-ray line widths; the range of energies to which the ...
This syntax uses the indices h, k, and ℓ as directional parameters. [4] By definition, the syntax (hkℓ) denotes a plane that intercepts the three points a 1 /h, a 2 /k, and a 3 /ℓ, or some multiple thereof. That is, the Miller indices are proportional to the inverses of the intercepts of the plane with the unit cell (in the basis of the ...