Chemical speciation via X-ray emission spectroscopy in the tender X-ray range

2016 ◽  
Vol 31 (2) ◽  
pp. 450-457 ◽  
Author(s):  
Marko Petric ◽  
Matjaž Kavčič
Keyword(s):  
Energy Resolution ◽  
Emission Spectroscopy ◽  
Chemical Speciation ◽  
Full Range ◽  
Emission Spectra ◽  
High Energy ◽  
Oxidation States ◽  
High Energy Resolution ◽  
X Ray

Kα X-ray emission spectra from a series of phosphorus, sulfur, and chlorine containing compounds covering the full range of oxidation states were measured employing high energy resolution proton induced X-ray emission (PIXE) spectroscopy in the tender X-ray range.

scholarly journals High-energy resolution X-ray absorption and emission spectroscopy reveals insight into unique selectivity of La-based nanoparticles for CO2

2015 ◽  
Vol 112 (52) ◽  
pp. 15803-15808 ◽  
Author(s):  
Ofer Hirsch ◽  
Kristina O. Kvashnina ◽  
Li Luo ◽  
Martin J. Süess ◽  
Pieter Glatzel ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Emission Spectroscopy ◽  
High Energy ◽  
Unit Cell ◽  
High Energy Resolution ◽  
Electron Configuration ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

The lanthanum-based materials, due to their layered structure and f-electron configuration, are relevant for electrochemical application. Particularly, La2O2CO3 shows a prominent chemoresistive response to CO2. However, surprisingly less is known about its atomic and electronic structure and electrochemically significant sites and therefore, its structure–functions relationships have yet to be established. Here we determine the position of the different constituents within the unit cell of monoclinic La2O2CO3 and use this information to interpret in situ high-energy resolution fluorescence-detected (HERFD) X-ray absorption near-edge structure (XANES) and valence-to-core X-ray emission spectroscopy (vtc XES). Compared with La(OH)3 or previously known hexagonal La2O2CO3 structures, La in the monoclinic unit cell has a much lower number of neighboring oxygen atoms, which is manifested in the whiteline broadening in XANES spectra. Such a superior sensitivity to subtle changes is given by HERFD method, which is essential for in situ studying of the interaction with CO2. Here, we study La2O2CO3-based sensors in real operando conditions at 250 °C in the presence of oxygen and water vapors. We identify that the distribution of unoccupied La d-states and occupied O p- and La d-states changes during CO2 chemoresistive sensing of La2O2CO3. The correlation between these spectroscopic findings with electrical resistance measurements leads to a more comprehensive understanding of the selective adsorption at La site and may enable the design of new materials for CO2 electrochemical applications.

scholarly journals Resonant inelastic X-ray scattering using a miniature dispersive Rowland refocusing spectrometer

2020 ◽  
Vol 27 (2) ◽  
pp. 446-454
Author(s):  
Alexander S. Ditter ◽  
William M. Holden ◽  
Samantha K. Cary ◽  
Veronika Mocko ◽  
Matthew J. Latimer ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Emission Spectroscopy ◽  
Spot Size ◽  
High Energy ◽  
Extensive Study ◽  
High Energy Resolution ◽  
X Ray ◽  
X Ray Scattering ◽  
Scientific Mission ◽  
Ray Scattering

X-ray absorption spectroscopy (XAS) beamlines worldwide are steadily increasing their emphasis on full photon-in/photon-out spectroscopies, such as resonant inelastic X-ray scattering (RIXS), resonant X-ray emission spectroscopy (RXES) and high energy resolution fluorescence detection XAS (HERFD-XAS). In such cases, each beamline must match the choice of emission spectrometer to the scientific mission of its users. Previous work has recently reported a miniature tender X-ray spectrometer using a dispersive Rowland refocusing (DRR) geometry that functions with high energy resolution even with a large X-ray spot size on the sample [Holden et al. (2017). Rev. Sci. Instrum. 88, 073904]. This instrument has been used in the laboratory in multiple studies of non-resonant X-ray emission spectroscopy using a conventional X-ray tube, though only for preliminary measurements at a low-intensity microfocus synchrotron beamline. This paper reports an extensive study of the performance of a miniature DRR spectrometer at an unfocused wiggler beamline, where the incident monochromatic flux allows for resonant studies which are impossible in the laboratory. The results support the broader use of the present design and also suggest that the DRR method with an unfocused beam could have important applications for materials with low radiation damage thresholds and that would not survive analysis on focused beamlines.

scholarly journals Multi-resolution electron spectrometer array for future free-electron laser experiments

2021 ◽  
Vol 28 (5) ◽  
pp. 1364-1376
Author(s):  
Peter Walter ◽  
Andrei Kamalov ◽  
Averell Gatton ◽  
Taran Driver ◽  
Dileep Bhogadi ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Free Electron ◽  
Full Range ◽  
High Energy ◽  
High Energy Resolution ◽  
Energy Structure ◽  
Full Time ◽  
Interaction Point ◽  
X Ray ◽  
Non Invasive

The design of an angular array of electron time-of-flight (eToF) spectrometers is reported, intended for non-invasive spectral, temporal, and polarization characterization of single shots of high-repetition rate, quasi-continuous, short-wavelength free-electron lasers (FELs) such as the LCLS II at SLAC. This array also enables angle-resolved, high-resolution eToF spectroscopy to address a variety of scientific questions on ultrafast and nonlinear light–matter interactions at FELs. The presented device is specifically designed for the time-resolved atomic, molecular and optical science endstation (TMO) at LCLS II. In its final version, the spectrometer comprises up to 20 eToF spectrometers aligned to collect electrons from the interaction point, which is defined by the intersection of the incoming FEL radiation and a gaseous target. The full composition involves 16 spectrometers forming a circular equiangular array in the plane normal to the X-ray propagation and four spectrometers at 54.7° angle relative to the principle linear X-ray polarization axis with orientations in the forward and backward direction of the light propagation. The spectrometers are capable of independent and minimally chromatic electrostatic lensing and retardation, in order to enable simultaneous angle-resolved photo- and Auger–Meitner electron spectroscopy with high energy resolution. They are designed to ensure an energy resolution of 0.25 eV across an energy window of up to 75 eV, which can be individually centered via the adjustable retardation to cover the full range of electron kinetic energies relevant to soft X-ray methods, 0–2 keV. The full spectrometer array will enable non-invasive and online spectral-polarimetry measurements, polarization-sensitive attoclock spectroscopy for characterizing the full time–energy structure of SASE or seeded LCLS II pulses, and support emerging trends in molecular-frame spectroscopy measurements.

Mn 2p resonant X-ray emission clarifies the redox reaction and charge-transfer effects in LiMn2O4

2019 ◽  
Vol 21 (33) ◽  
pp. 18363-18369 ◽  
Author(s):  
Daisuke Asakura ◽  
Yusuke Nanba ◽  
Eiji Hosono ◽  
Masashi Okubo ◽  
Hideharu Niwa ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Charge Transfer ◽  
Energy Resolution ◽  
Emission Spectroscopy ◽  
High Energy ◽  
High Energy Resolution ◽  
Transfer Effects ◽  
X Ray ◽  
Ion Extraction ◽  
Li Ion

High-energy-resolution soft X-ray emission spectroscopy (XES) was applied to understand the changes in the electronic structure of LiMn2O4 upon Li-ion extraction/insertion.

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