scholarly journals High-Resolution Core-Level Photoabsorption of Alkali Halides

1993 ◽  
Vol 307 ◽  
Author(s):  
E. Hudson ◽  
E. Moler ◽  
Y. Zheng ◽  
S. Kellar ◽  
P. Heimann ◽  
...  
Keyword(s):  
Alkali Halides ◽  
High Energy ◽  
Core Level ◽  
High Energy Resolution ◽  
X Rays ◽  
Edge Structure ◽  
Photoabsorption Spectrum ◽  
Halide Salts ◽  
X Ray Absorption ◽  
Absorption Features

ABSTRACTThe X-ray Absorption Near Edge Structure (XANES) of single-crystal alkali halide salts have been measured at low temperature (T≈80 K). By employing the electron partial-yield detection technique, spectra of NaF, NaCI, and NaBr were obtained near the sodium K-edge and spectra of LiF, NaF, and KF were obtained near the fluorine K-edge. All spectra showed sharp features at the absorption threshold and broader absorption features extending 50–80 eV above threshold. The high energy resolution of the soft X-rays (ΔE/E ≈ 4000) allowed the detection of previously unobserved fine structure, particularly in the near-edge region. The narrow features below and just above threshold are attributed to core-level excitons. The intense, broader peaks further above threshold are assigned to single-electron scattering resonances. An ab initio multiple-scattering calculation is used to model the latter effect. Contributions from atomic multielectron excitations, estimated by a comparison to the K-edge photoabsorption spectrum of Ne in the gas phase, are found to be very small.

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.

Time-resolved XAFS measurement using quick-scanning techniques at BSRF

2017 ◽  
Vol 24 (3) ◽  
pp. 674-678 ◽  
Author(s):  
Shengqi Chu ◽  
Lirong Zheng ◽  
Pengfei An ◽  
Hui Gong ◽  
Tiandou Hu ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
High Energy ◽  
High Energy Resolution ◽  
Double Crystal ◽  
Time Resolved ◽  
Edge Structure ◽  
X Ray ◽  
Double Crystal Monochromator ◽  
Good Signal ◽  
X Ray Absorption

A new quick-scanning X-ray absorption fine-structure (QXAFS) system has been established on beamline 1W1B at the Beijing Synchrotron Radiation Facility. As an independent device, the QXAFS system can be employed by other beamlines equipped with a double-crystal monochromator to carry out quick energy scans and data acquisition. Both continuous-scan and trapezoidal-scan modes are available in this system to satisfy the time scale from subsecond (in the X-ray absorption near-edge structure region) to 1 min. Here, the trapezoidal-scan method is presented as being complementary to the continuous-scan method, in order to maintain high energy resolution and good signal-to-noise ratio. The system is demonstrated to be very reliable and has been combined with in situ cells to carry out time-resolved XAFS studies.

scholarly journals Implementation of cryogenic tender X-ray HR-XANES spectroscopy at the ACT station of the CAT-ACT beamline at the KIT Light Source

2022 ◽  
Vol 29 (1) ◽  
Author(s):  
Bianca Schacherl ◽  
Tim Prüssmann ◽  
Kathy Dardenne ◽  
Kirsten Hardock ◽  
Volker Krepper ◽  
...  
Keyword(s):  
Light Source ◽  
High Energy ◽  
Xanes Spectroscopy ◽  
Nuclear Waste Repository ◽  
X Rays ◽  
Edge Structure ◽  
X Ray ◽  
Analyzer Crystal ◽  
Institute Of Technology ◽  
X Ray Absorption

The ACT experimental station of the CAT-ACT wiggler beamline at the Karlsruhe Institute of Technology (KIT) Light Source is dedicated to the investigation of radionuclide materials with radioactivities up to 1000000 times the exemption limit by various speciation techniques applying monochromatic X-rays. In this article, the latest technological developments at the ACT station that enable high-resolution X-ray absorption near-edge structure (HR-XANES) spectroscopy for low radionuclide loading samples are highlighted – encompassing the investigation of actinide elements down to 1 p.p.m. concentration – combined with a cryogenic sample environment reducing beam-induced sample alterations. One important part of this development is a versatile gas tight plexiglass encasement ensuring that all beam paths in the five-analyzer-crystal Johann-type X-ray emission spectrometer run within He atmosphere. The setup enables the easy exchange between different experiments (conventional X-ray absorption fine structure, HR-XANES, high-energy or wide-angle X-ray scattering, tender to hard X-ray spectroscopy) and opens up the possibility for the investigation of environmental samples, such as specimens containing transuranium elements from contaminated land sites or samples from sorption and diffusion experiments to mimic the far field of a breached nuclear waste repository.

scholarly journals Probing CuI in homogeneous catalysis using high-energy-resolution fluorescence-detected X-ray absorption spectroscopy

2015 ◽  
Vol 51 (48) ◽  
pp. 9864-9867 ◽  
Author(s):  
Richard C. Walroth ◽  
Jacob W. H. Uebler ◽  
Kyle M. Lancaster
Keyword(s):  
Charge Transfer ◽  
Homogeneous Catalysis ◽  
Energy Resolution ◽  
Catalytic Reaction ◽  
High Energy ◽  
High Energy Resolution ◽  
X Ray ◽  
Ligand Charge Transfer ◽  
X Ray Absorption ◽  
Absorption Features

CuI X-ray absorption features are assigned as metal-to-ligand charge transfer bands. These features facilitate species identification in catalytic reaction mixtures.

scholarly journals High-resolution X-ray absorption spectroscopy of iron carbonyl complexes

2015 ◽  
Vol 17 (21) ◽  
pp. 13937-13948 ◽  
Author(s):  
Andrew J. Atkins ◽  
Matthias Bauer ◽  
Christoph R. Jacob
Keyword(s):  
High Resolution ◽  
Absorption Spectroscopy ◽  
Energy Resolution ◽  
High Energy ◽  
Iron Carbonyl ◽  
High Energy Resolution ◽  
Carbonyl Complexes ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

We apply high-energy-resolution fluorescence-detected (HERFD) X-ray absorption near-edge structure (XANES) spectroscopy to study iron carbonyl complexes.

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

The (1×1)→hexagonal structural transition on Pt(100) studied by high-energy resolution core level photoemission

2007 ◽  
Vol 127 (16) ◽  
pp. 164702 ◽  
Author(s):  
Alessandro Baraldi ◽  
Erik Vesselli ◽  
Laura Bianchettin ◽  
Giovanni Comelli ◽  
Silvano Lizzit ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Structural Transition ◽  
High Energy ◽  
Core Level ◽  
High Energy Resolution

High-energy resolution in X-ray scattering with the spectrometer INELAX. I. The principles and the test instrument

1991 ◽  
Vol 24 (6) ◽  
pp. 1042-1050 ◽  
Author(s):  
E. Burkel ◽  
B. Dorner ◽  
Th. Illini ◽  
J. Peisl
Keyword(s):  
Energy Resolution ◽  
High Energy ◽  
Bragg Angle ◽  
High Energy Resolution ◽  
X Rays ◽  
Test Results ◽  
X Ray Scattering ◽  
Radiation Sources ◽  
Very High Energy ◽  
Very High

Very high-energy resolution measurements using X-rays can be achieved by extreme backreflection (Bragg angle close to 90°) from perfect crystals. This technique, combined with the high intensity of X-rays emitted by synchrotron-radiation sources, allowed the development of the instrument INELAX for inelastic scattering experiments. The principles and test results are discussed.

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