The discovery of a new physical process in manganese metal is reported. This process will also be present for all manganese‐containing materials in condensed matter. The process was discovered by ...applying our new technique of XR‐HERFD (extended‐range high‐energy‐resolution fluorescence detection), which was developed from the popular high‐resolution RIXS (resonant inelastic X‐ray scattering) and HERFD approaches. The acquired data are accurate to many hundreds of standard deviations beyond what is regarded as the criterion for `discovery'. Identification and characterization of many‐body processes can shed light on the X‐ray absorption fine‐structure spectra and inform the scientist on how to interpret them, hence leading to the ability to measure the dynamical nanostructures which are observable using the XR‐HERFD method. Although the many‐body reduction factor has been used universally in X‐ray absorption spectroscopy in analysis over the past 30 years (thousands of papers per year), this experimental result proves that many‐body effects are not representable by any constant reduction factor parameter. This paradigm change will provide the foundation for many future studies and X‐ray spectroscopy.
A new physical process in manganese, present for manganese‐containing materials and materials science, has been discovered by applying our new technique – XR‐HERFD (extended‐range high‐energy‐resolution fluorescence detection) – developed from high‐resolution RIXS (resonant inelastic X‐ray scattering) and HERFD (high‐energy‐resolution fluorescence detection).
The most accurate measurements of the mass attenuation coefficient for metals at low temperature for the zinc K‐edge from 9.5 keV to 11.5 keV at temperatures of 10 K, 50 K, 100 K and 150 K using the ...hybrid technique are reported. This is the first time transition metal X‐ray absorption fine structure (XAFS) has been studied using the hybrid technique and at low temperatures. This is also the first hybrid‐like experiment at the Australian Synchrotron. The measured transmission and fluorescence XAFS spectra are compared and benchmarked against each other with detailed systematic analyses. A recent method for modelling self‐absorption in fluorescence has been adapted and applied to a solid sample. The XAFS spectra are analysed using eFEFFIT to provide a robust measurement of the evolution of nanostructure, including such properties as net thermal expansion and mean‐square relative displacement. This work investigates crystal dynamics, nanostructural evolution and the results of using the Debye and Einstein models to determine atomic positions. Accuracies achieved, when compared with the literature, exceed those achieved by both relative and differential XAFS, and represent a state‐of‐the‐art for future structural investigations. Bond length uncertainties are of the order of 20–40 fm.
High‐accuracy measurement of the X‐ray absorption fine structure (XAFS) of zinc metal in a temperature series from 10 K to 150 K, including 298 K, simultaneously in transmission and fluorescence using the hybrid technique is presented: the first transition metal XAFS using the hybrid technique and at low temperatures; and the first (hybrid‐like) experiment at the Australian Synchrotron. A methodology for relative measurements and a methodology for cryostat measurements, and an approach to normalization, calibration of transmission measurements for scattering and other systematics to reference room‐temperature data and yield a defined uncertainty are presented.
Here, the novel technique of extended-range high-energy-resolution fluorescence detection (XR-HERFD) has successfully observed the n = 2 satellite in manganese to a high accuracy. The significance of ...the satellite signature presented is many hundreds of standard errors and well beyond typical discovery levels of three to six standard errors. This satellite is a sensitive indicator for all manganese-containing materials in condensed matter. The uncertainty in the measurements has been defined, which clearly observes multiple peaks and structure indicative of complex physical quantum-mechanical processes. Theoretical calculations of energy eigenvalues, shake-off probability and Auger rates are also presented, which explain the origin of the satellite from physical n = 2 shake-off processes. The evolution in the intensity of this satellite is measured relative to the full K α spectrum of manganese to investigate satellite structure, and therefore many-body processes, as a function of incident energy. Results demonstrate that the many-body reduction factor S 0 2 should not be modelled with a constant value as is currently done. This work makes a significant contribution to the challenge of understanding many-body processes and interpreting HERFD or resonant inelastic X-ray scattering spectra in a quantitative manner.
We present a method to explore the effect of fluorescence on X‐ray attenuation measurements obtained from X‐ray absorption spectroscopy (XAS). We use the X‐ray extended range technique‐like method ...(XERT‐like). The experimental setup includes different sized apertures to control the number of secondary X‐rays entering the detector. Comparison of attenuation measurements produced with different aperture combination permit investigation of the effect of fluorescence radiation. In this work, fluorescence has a large impact on the attenuation measurements of thick zinc foils. The correction is energy‐dependent and sample thickness‐dependent and changes the structure and relative amplitudes of oscillations in the near‐edge region. Correction for this systematic is important for absolute measurement, for edge‐jump and edge characterization, and for near‐edge structure and amplitudes. A significant background scattering due to zinc fluorescence from the beamline optics was identified and treated for the first time. The model theory fits the experimental measurements well. The resulting correction is most significant for thicker foils with the 50 μm sample experiencing a shift in attenuation of up to 15.5% for the largest aperture while the 25 and 10 μm samples saw corrections of up to 0.153 and 0.00639% respectively. The standard error from the dispersion and variance was reduced by up to 50.5% after the correction for the 50 μm sample. This enables high‐accuracy data and theoretical and experimental analysis to below 0.03% accuracy. The technology is advanced. There is a cost in preparation and measurement time of less than a factor of two, and the principles are clear and can be routinely implemented on any beamline. This paper focuses on the model and parameters for fluorescence.
The first X‐ray Extended Range Technique (XERT)‐like experiment at the Australian Synchrotron, Australia, is presented. In this experiment X‐ray mass attenuation coefficients are measured across an ...energy range including the zinc K‐absorption edge and X‐ray absorption fine structure (XAFS). These high‐accuracy measurements are recorded at 496 energies from 8.51 keV to 11.59 keV. The XERT protocol dictates that systematic errors due to dark current nonlinearities, correction for blank measurements, full‐foil mapping to characterize the absolute value of attenuation, scattering, harmonics and roughness are measured over an extended range of experimental parameter space. This results in data for better analysis, culminating in measurement of mass attenuation coefficients across the zinc K‐edge to 0.023–0.036% accuracy. Dark current corrections are energy‐ and structure‐dependent and the magnitude of correction reached 57% for thicker samples but was still large and significant for thin samples. Blank measurements scaled thin foil attenuation coefficients by 60–500%; and up to 90% even for thicker foils. Full‐foil mapping and characterization corrected discrepancies between foils of up to 20%, rendering the possibility of absolute measurements of attenuation. Fluorescence scattering was also a major correction. Harmonics, roughness and bandwidth were explored. The energy was calibrated using standard reference foils. These results represent the most extensive and accurate measurements of zinc which enable investigations of discrepancies between current theory and experiments. This work was almost fully automated from this first experiment at the Australian Synchrotron, greatly increasing the possibility for large‐scale studies using XERT.
The first X‐ray Extended Range Technique (XERT)‐like experiment at the Australian Synchrotron measured 496 energies from 8.51 keV to 11.59 keV for zinc metal to 0.023–0.036% accuracy. Systematics are quantified.
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.
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.
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