Microcalorimeter EDS Measurements of Chemical Shifts in Fe Compounds

1998 ◽  
Vol 4 (S2) ◽  
pp. 196-197 ◽  
Author(s):  
D. A. Wollman ◽  
Dale E. Newbury ◽  
G. C. Hilton ◽  
K. D. Irwin ◽  
L. L. Dulcie ◽  
...  
Keyword(s):  
Chemical Shifts ◽  
Energy Dispersive Spectrometer ◽  
Emission Spectra ◽  
High Energy ◽  
Peak Position ◽  
Binding Energies ◽  
High Energy Resolution ◽  
X Ray ◽  
Valence Electrons ◽  
Electron Binding Energies

We report measurements of chemical shifts in the Fe-L x-ray lines of different Fe compounds from xray emission spectra acquired using a microcalorimeter energy dispersive spectrometer (EDS). The observed changes in peak position and relative intensity of the Fe-L x-ray lines are in agreement with measurements obtained using a wavelength dispersive spectrometer (WDS), demonstrating the usefulness of microcalorimeter EDS for high-energy-resolution x-ray microanalysis.Chemical shifts result from changes in electron binding energies with the chemical environment of atoms. In x-ray spectra, chemical shifts lead to changes in x-ray peak positions, relative peak intensities, and peak shapes. These chemical bonding effects can be significant (with x-ray peak shifts on the order of 1 eV), particularly for x-ray lines resulting from transitions involving valence electrons of light elements such as B and C.

X-ray photoelectron spectroscopic (XPS) studies of iodine oxocompounds

1988 ◽  
Vol 53 (3) ◽  
pp. 425-432 ◽  
Author(s):  
Zdeněk Bastl ◽  
Heidrun Gehlmann
Keyword(s):  
Cross Sections ◽  
Chemical Shifts ◽  
Theoretical Data ◽  
Binding Energies ◽  
Oxidation States ◽  
Core Electron ◽  
X Ray ◽  
The Core ◽  
Quantitative Surface Analysis ◽  
Electron Binding Energies

The core electron binding energies of eighteen compounds containing iodine in different oxidation states ranging from (-I) to (VII) have been measured. The observed chemical shifts differ from the literature data. The anticipated existence of hexavalent iodine in certain compounds has not been demonstrated. The relative subshell photoemission intensities of iodine have been determined. Empirically derived atomic sensitivity factors and theoretical photoionization cross-sections have been used to calculate the surface stoichiometry. The concentration ratios obtained via the two methods are compared. In agreement with generally accepted view the results of this comparison imply that, for quantitative surface analysis, empirical values should be used rather than theoretical data.

Development of a WDX-μ-PIXE system for chemical state mapping

2014 ◽  
Vol 24 (03n04) ◽  
pp. 111-120 ◽  
Author(s):  
S. Toyama ◽  
S. Matsuyama ◽  
K. Ishii ◽  
A. Terakawa ◽  
K. Kasahara ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Energy Resolution ◽  
Detection Efficiency ◽  
Chemical Shifts ◽  
Ccd Camera ◽  
High Energy ◽  
Chemical State ◽  
High Energy Resolution ◽  
Clay Particles ◽  
X Ray

In this paper, we have developed a wavelength dispersive X-ray spectrometer microparticle-induced X-ray emission (WDX-[Formula: see text]-PIXE) system combining a microbeam system with high spatial resolution and wavelength dispersive X-ray (WDX) spectrometry with high-energy resolution for chemical state mapping. A Von Hamos geometry was used for the WDX system to achieve higher detection efficiency and energy resolution. The system consists of a curved crystal and a CCD camera. The WDX system was installed in a newly developed microbeam system. The energy resolution of the WDX system was 0.67 eV for [Formula: see text] (1740 eV). [Formula: see text] and [Formula: see text] X-ray spectra from various Si compounds were measured and chemical shifts related to chemical states were clearly observed. The system was applied to the chemical state analysis of clay particles. After elemental mapping of the clay particles using a conventional [Formula: see text]-PIXE system with a Si(Li) detector, particles to be analyzed were selected and analyzed sequentially with the WDX system. [Formula: see text] spectra from clay particles were obtained. The microscopic spatial distribution of elements and chemical state of the clay particles were sequentially measured with high energy and spatial resolution using a microbeam.

A High Energy-resolution Wavelength-dispersive Soft-X-ray Spectrometer for a Transmission Electron Microscope to Investigate Valence Electrons

2004 ◽  
Vol 10 (S02) ◽  
pp. 1044-1045 ◽  
Author(s):  
Masami Terauchi
Keyword(s):  
Electron Microscope ◽  
Energy Resolution ◽  
Transmission Electron Microscope ◽  
High Energy ◽  
High Energy Resolution ◽  
X Ray ◽  
Transmission Electron ◽  
Valence Electrons

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

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 Fluorescence-Detected X-ray Absorption of the Q Intermediate of Soluble Methane Monooxygenase

2017 ◽  
Vol 139 (49) ◽  
pp. 18024-18033 ◽  
Author(s):  
Rebeca G. Castillo ◽  
Rahul Banerjee ◽  
Caleb J. Allpress ◽  
Gregory T. Rohde ◽  
Eckhard Bill ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Methane Monooxygenase ◽  
High Energy ◽  
High Energy Resolution ◽  
X Ray ◽  
Soluble Methane Monooxygenase ◽  
X Ray Absorption

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 Plasma diagnostics using Kα satellite emission spectroscopy in light ion beam fusion experiments

1995 ◽  
Vol 13 (2) ◽  
pp. 231-241 ◽  
Author(s):  
J.J. MacFarlane ◽  
P. Wang ◽  
J.E. Bailey ◽  
T.A. Mehlhorn ◽  
R.J. Dukart
Keyword(s):  
Emission Spectroscopy ◽  
Impact Ionization ◽  
Ion Beam ◽  
Emission Spectra ◽  
Particle Beam ◽  
High Energy ◽  
Atomic Level ◽  
High Energy Density ◽  
Equilibrium Equations ◽  
X Ray

Kα satellite spectroscopy can be a valuable technique for diagnosing conditions in high energy density plasmas. Kα emission lines are produced in intense light ion beam plasma interaction experiments as 2p electrons fill partially open Is shells created by the ion beam. In this paper, we present results from collisional-radiative equilibrium (CRE) calculations which show how Kα emission spectroscopy can be used to determine target plasma conditions in intense lithium beam experiments on Particle Beam Fusion Accelerator-II (PBFAII) at Sandia National Laboratories. In these experiments, 8–10 MeV lithium beams with intensities of 1–2 TW/cm2 irradiate planar multilayer targets containing a thin Al tracer. Kα emission spectra are measured using an X-ray crystal spectrometer with a resolution of λ/∆λ = 1200. The spectra are analyzed using a CRE model in which multilevel (NL ∼ 103) statistical equilibrium equations are solved self-consistently with the radiation field and beam properties to determine atomic level populations. Atomic level-dependent fluorescence yields and ion-impact ionization cross sections are used in computing the emission spectra. We present results showing the sensitivity of the Kα emission spectrum to temperature and density of the Al tracer. We also discuss the dependence of measured spectra on the X-ray crystal spectral resolution, and how additional diagnostic information could be obtained using multiple tracers of similar atomic number.

scholarly journals Flow Cell for Operando X-Ray Photon-in-Photon-out Studies on Photo-Electrochemical Thin Film Devices

2020 ◽  
Author(s):  
Philipp Jäker ◽  
Dino Aegerter ◽  
Till Kyburz ◽  
Roman Staedler ◽  
Rea Fonjallaz ◽  
...  
Keyword(s):  
Thin Film ◽  
Water Oxidation ◽  
High Energy ◽  
Operating Conditions ◽  
High Energy Resolution ◽  
X Ray ◽  
Long Term Stability ◽  
Operando Xas ◽  
Artificial Photosynthetic ◽  
Thin Film Devices

Photo-electro-chemical (PEC) water splitting represents a promising technology towards an artificial photosynthetic device but many fundamental electronic processes, which govern long-term stability and energetics are not well understood. X-ray absorption spectroscopy (XAS), particularly its high energy resolution fluorescence-detected (HERFD) mode, emerges as a powerful tool to study photo-excited charge carrier behavior under operating conditions. The established thin film device architecture of PEC cells provides a well-defined measurement geometry, but it puts many constraints on conducting operando XAS experiments. So far, operando cells have not been developed that enable to concurrently measure highly intense X-ray fluorescence and photo-electro-chemical current without experimental artifacts caused by O<sub>2</sub> and H<sub>2</sub> bubbles formation. Moreover, we are missing a standardized thin film exchange procedure. Here, we address and overcome the instrumental limitations for operando HERFD-XAS to investigate photo- and electrochemical thin film devices. Our cell establishes a measurement routine that will provide experimental access to a broader scientific community, particularly due to the ease of sample exchange. Our operando photo-electro-chemical cell is optimized for the HERFD-XAS geometry and we demonstrate its operation by collecting high-resolution Fe K-edge spectra of hematite (α-Fe<sub>2</sub>O<sub>3</sub>) and ferrite thin film (MFe<sub>2</sub>O<sub>4</sub>, M= Zn, Ni) photoelectrodes during water oxidation.<br>

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