A general procedure which computes X-ray absorption near-edge structure (XANES) spectra starting from the individual configurations obtained from molecular dynamics (MD) simulations has been developed. This method allows one to perform a quantitative analysis of the XANES spectra of disordered systems and to estimate the effect of disorder on the low-energy region of the X-ray absorption spectra. As a test case, a Ni2+ aqueous solution has been investigated. The configurational averaged XANES theoretical spectrum obtained from the MD configurations compares well with the experimental data. This confirms simultaneously the reliability of the procedure and of the structural results obtained from the MD simulation.
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http://dx.doi.org/10.1107/S0909049504028808 | DOI Listing |
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January 2025
Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, College of Physics and Energy, Fujian Normal University, Fuzhou, Fujian, 350117, China.
Single-atom materials provide a platform to precisely regulate the electrochemical redox behavior of electrode materials with atomic level. Here, a multifield-regulated sintering route is reported to rapidly prepare single-atom zinc with a very high loading mass of 24.7 wt.
View Article and Find Full Text PDFWater Res
December 2024
Institute for Advanced Membrane Technology (IAMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany. Electronic address:
Calcium (Ca)-enhanced organic matter (OM) fouling of nanofiltration (NF) membranes leads to reduced flux during desalination and requires frequent cleaning. Fouling mechanisms are not fully understood, which limits the development of targeted fouling control methods. This study employed synchrotron-based X-ray fluorescence (XRF) and X-ray absorption near-edge structure (XANES) spectroscopy to quantify the spatial distribution and mass of Ca deposition as well as changes in the Ca coordination environment characteristic of specific fouling mechanisms, respectively.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States.
The fact that the photoabsorption spectrum of a material contains information about the atomic structure, commonly understood in terms of multiple scattering theory, is the basis of the popular extended X-ray absorption spectroscopy (EXAFS) technique. How much of the same structural information is present in other complementary spectroscopic signals is not obvious. Here we use a machine learning approach to demonstrate that within theoretical models that accurately predict the EXAFS signal, the extended near-edge region does indeed contain the EXAFS-accessible structural information.
View Article and Find Full Text PDFData Brief
October 2024
Department of Physics and Astronomy, UTRGV, Edinburg, TX, 78539, USA.
Dalton Trans
December 2024
Institute for Quantum Life Science, National Institutes for Quantum Science and Technology (QST), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
X-ray absorption near edge structure (XANES) spectra of blue copper proteins, amicyanin and azurin, in the solution state were measured in the copper L-edge energy region. The absorption peak energies were quite similar for both proteins, while the main edge region for azurin was broader than that for amicyanin, owing to more pronounced shoulder spectral features in the former. calculations at the whole protein level qualitatively reproduced the experimental spectra well.
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