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MM: Fachverband Metall- und Materialphysik
MM 12: Materials for the Storage and Conversion of Energy III / Functional Materials I
MM 12.3: Vortrag
Dienstag, 10. März 2026, 10:45–11:00, SCH/A216
Theoretical Calculation of Finite-Temperature X-Ray Absorption Fine Structure: Application to Sodium K-Edge in NaCl — Philipp Hönicke1,2, Yves Kayser3, and •Pouya Partovi-Azar4 — 1Helmholtz-Zentrum Berlin (HZB), Hahn-Meitner-Platz 1, 14109 Berlin, Germany — 2Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany — 3Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany — 4Institute of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
A comprehensive computational framework for calculating the full X-ray absorption fine structure (XAFS) through quantum-chemical simulations is presented. The near-edge region is accurately captured using time-dependent density-functional perturbation theory applied to core excitations, while ab initio molecular dynamics provides sampling of core-excitation energies and interatomic distance distributions for interpreting extended X-ray absorption fine structure (EXAFS) features. Owing to the efficiency of the approach, the total spectrum can be decomposed into contributions from bulk, defective, and surface environments, which commonly coexist in experimental systems. The methodology is demonstrated for sodium at the Na K-edge in NaCl, where the predicted spectra show good agreement with experimental measurements on thin film samples. This strategy offers a practical route to generating chemically specific XAFS cross-section data for elements that remain challenging to characterize experimentally.
Keywords: TDDFT; ab initio molecular dynamics; X-ray absorption spectroscopy; XANES; EXAFS