Chemical Effects in Hard X‐ray Photon‐In Photon‐Out Spectra

Abstract

Hard X‐ray photon‐in photon‐out techniques are targeted at applications where the sample environment cannot be freely chosen. The resultant X‐ray emission spectra are influenced by the chemical environments of the atoms involved. If high‐resolution measurements are possible, the chemical effects in the X‐ray emission spectra can provide information about the chemical states, complementary to that offered by other X‐ray spectroscopies. X‐ray emission is classified into six categories for convenience: X‐ray diagram lines, X‐ray valence‐band emission, radiative Auger effect, resonant X‐ray emission, Compton scattering, and X‐ray Raman scattering. After a brief description of the history of research on these types of emission, the chemical effects that they reveal and related topics, including high‐resolution absorption measurements and the static structure factor, are reviewed. An overview of the instrumentation employed in both laboratories and synchrotron radiation (SR) facilities is also given.

TEXS: in-vacuum tender X-ray emission spectrometer with 11 Johansson crystal analyzers

“…The spectroscopic techniques with such an instrument include nonresonant x-ray emission spectroscopy (XES), that does not require a monochromatic incoming beam to excite the analyte atom, as well as resonant inelastic x-ray scattering (RIXS) and high energy resolution fluorescence detected (HERFD) x-ray absorption near edge structure (XANES) spectroscopy. A series of books and review papers describes the applications of XES, RIXS and HERFD-XANES in solid state physics, materials science, coordination chemistry and biology [1][2][3][4][5][6][7][8][9] . High performance and user-friendly x-ray emission spectrometers at synchrotron radiation facilities and in the laboratory, combined with tools for theoretical interpretation of the data, have greatly helped the adoption of the techniques by a large community.…”

Low-Cost, High-Performance Sample Cell for X-Ray Spectroscopy of Solutions and Gels Made from Plastic Straw

“…Such an apparent shift is problematic in chemical state analysis using highly resolved XRF. 23,24 Figure 4(b) shows high-resolution Fe Kβ1,3 spectra of α-Fe2O3, K3[Fe(CN)6], and K4[Fe(CN)6]•3H2O powder in the straw cells, obtained under the same measurement conditions. As reported in the literature, 24 the spectra differed substantially, depending on the chemical environment of the Fe atoms; the Kβ emissions of 3d elements are known to be dominated by the 3p-3d exchange interaction, and are hence sensitive to the spin states of 3d atoms.…”

In vivo time‐resolved X‐ray fluorescence mapping measurements of Egeria densa immersed in Cr(VI) aqueous solution

“…[34] The oxidation states of the Cr species in the 'rootless' E. densa are not clear and, unfortunately, cannot be determined by the present low-energy resolution (~200 eV) experiments. The in vivo oxidation state analysis of Cr in E. densa is an interesting future task; X-ray absorption fine structure [21,22,24,33] and/or high-energy resolution (~1 eV) X-ray emission spectroscopies [14,34,35] may be helpful for addressing this issue. Figure 7 depicts the changes in the total Cr XRF signal intensity from the Cr hot spots (the Cr signal intensity integrated over the entire hot spot area) with respect to elapsed time.…”