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  • Parametrized ion-distribution model for extended x-ray absorption fine-structure analysis at high-energy-density conditions
Title: Parametrized ion-distribution model for extended x-ray absorption fine-structure analysis at high-energy-density conditions
Experiments today can compress solids near isentropically to pressures approaching 100 × 106 atmospheres; however, determining the temperature of such matter remains a major challenge. Extended x-ray absorption fine-structure (EXAFS) spectroscopy is one of the few techniques sensitive to the bulk temperature of highly compressed solid matter, and the validity of this temperature measurement relies on constraining the local ion structure from the EXAFS spectrum. At high-energy-density (HED) conditions, the local ion structure often becomes distorted, which must be accounted for during the EXAFS analysis. Described here is a technique, using a parametrized ion-distribution model to directly analyze EXAFS spectra that provides a better constraint on the local structure than traditional second- or third-order cumulant expansion techniques at HED conditions. The parametrized ion-distribution model is benchmarked by analyzing EXAFS spectra from nickel molecular-dynamics simulations at ∼100 GPa and shown to provide a 10%–20% improvement in constraining the cumulants of the true ion distribution.  more » « less
Award ID(s):
2020249
PAR ID:
10591979
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
American Institute of Physics
Date Published:
Journal Name:
Physics of Plasmas
Volume:
31
Issue:
4
ISSN:
1070-664X
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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