High‐accuracy measurement of mass attenuation coefficients and the imaginary component of the atomic form factor of zinc from 8.51 keV to 11.59 keV, and X‐ray absorption fine structure with investigation of zinc theory and nanostructure. (19th July 2021)

• Record Type: Journal Article
• Authors: Ekanayake, Ruwini S. K.; Chantler, Christopher T.; Sier, Daniel; Schalken, Martin J.; Illig, Alexis J.; de Jonge, Martin D.; Johannessen, Bernt; Kappen, Peter; Tran, Chanh Q.
• Is Part Of: Journal of synchrotron radiation. Volume 28:Part 5(2021)
• Page Start: 1492
• Page End: 1503
• Publication Date: 2021-07-19
• Subjects: materials science -- nanoscience -- XAFS -- computational modelling -- density functional theory -- materials modelling -- nanostructure -- X‐ray mass attenuation coefficients -- atomic form factor -- XERT -- zinc; Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S1600577521005981
• Languages: English
• ISSNs: 0909-0495

Abstract

Abstract : Zinc metal XAFS to high accuracy determined K ‐edge jump ratio and jump factors, revealing significant issues in theory and experiment. Nanostructure of zinc is determined to high accuracy with bond lengths with uncertainties from 0.1% to 0.3% or 0.003 to 0.008 ÅA, suggesting local dynamic motion of the crystal lattice. Abstract : High‐accuracy X‐ray mass attenuation coefficients were measured from the first X‐ray Extended Range Technique (XERT)‐like experiment at the Australian Synchrotron. Experimentally measured mass attenuation coefficients deviate by ∼50% from the theoretical values near the zinc absorption edge, suggesting that improvements in theoretical tabulations of mass attenuation coefficients are required to bring them into better agreement with experiment. Using these values the imaginary component of the atomic form factor of zinc was determined for all the measured photon energies. The zinc K ‐edge jump ratio and jump factor are determined and results raise significant questions regarding the definitions of quantities used and best practice for background subtraction prior to X‐ray absorption fine‐structure (XAFS) analysis. The XAFS analysis shows excellent agreement between the measured and tabulated values and yields bond lengths and nanostructure of zinc with uncertainties of from 0.1% to 0.3% or 0.003 Å to 0.008 Å. Significant variation from the reported crystal structure was observed, suggesting local dynamic motion of the standard crystal lattice. XAFS is sensitive to dynamic correlated motion and in principle is capable of observing local dynamic motion beyond the reach of conventional crystallography. These results for the zinc absorption coefficient, XAFS and structure are the most accurate structural refinements of zinc at room temperature.