Reflection-Extended-X-Ray-Absorption-Fine-Structure Spectroscopy at the Carbon K-Edge

1988 ◽  
Vol 143 ◽  
Author(s):  
G. G. Long ◽  
D. R. Black ◽  
D. K. Tanaka
Keyword(s):  
Fine Structure ◽  
Phase Shift ◽  
Glassy Carbon ◽  
Surface Oxygen ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
Exafs Spectra

AbstractThe carbon K-edge Reflection-Extended X-Ray Absorption Fine Structure (refl-EXAFS) spectra from graphite, diamond and glassy carbon have been investigated. There is good phase shift transferability between the two well-known bonding types in diamond and graphite, provided that appropriate inner potential corrections to the K-edge energy E. are made. The model spectra from diamond and graphite were used to investigate the nature of glassy carbon. It was found that, for the particular form of glassy carbon used in this study, the bonding more closely resembled sp3 than sp2. This result is preliminary pending our evaluation of the influence of surface oxygen.

Model Extended X-ray Absorption Fine Structure (EXAFS) Spectra from Molecular Dynamics Data for Ca2+and Al3+Aqueous Solutions

2000 ◽  
Vol 104 (45) ◽  
pp. 10467-10472 ◽  
Author(s):  
Daniel Spångberg ◽  
Kersti Hermansson ◽  
Patric Lindqvist-Reis ◽  
Farideh Jalilehvand ◽  
Magnus Sandström ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Fine Structure ◽  
Aqueous Solutions ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
Exafs Spectra

Tracking of arsenics during the thermal stabilization of an AsH3 scrubber sludge

2013 ◽  
Vol 68 (9) ◽  
pp. 2007-2011 ◽  
Author(s):  
Chang-Yu Liao ◽  
Fang-Chih Chang ◽  
H. Paul Wang ◽  
Yu-Ling Wei ◽  
Chih-Ju G. Jou
Keyword(s):  
Fine Structure ◽  
High Temperature ◽  
Thermal Stabilization ◽  
Bonding Energy ◽  
Edge Structure ◽  
X Ray ◽  
Temperature Range ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
Exafs Spectra

Toxic arsenics in an AsH3 scrubber sludge were thermally stabilized in the temperature range of 973–1,373 K. To better understand how the high-temperature treatments can stabilize arsenics in the sludge, their synchrotron X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra of arsenics were determined. It is found that the reduced arsenic leachability may be associated with the formation of As2O5 (51–59%) and embedded As(V) within the Ca3(PO4)2 matrix (41–49%) in the stabilized sludge. In addition, the As-O bond distances in the stabilized As2O5 are much less than that of normal As2O5 by 0.05–0.07 Å. The shorter As-O bond distances accompanied with the higher bonding energy also have a contribution to the thermal stabilization of arsenics.

scholarly journals An Investigation of the Structure of Amorphous Co-P Alloys. 2: EXAFS at the Phosphorous K-edge, a Feasibility Study

1998 ◽  
Vol 53 (10-11) ◽  
pp. 848-854
Author(s):  
Mi. Nuding ◽  
P. Lamparter ◽  
S. Steeb ◽  
F. Neißendorfer ◽  
F. Schäfers
Keyword(s):  
Fine Structure ◽  
Phase Shift ◽  
Amorphous Alloys ◽  
Reference Sample ◽  
Exafs Spectrum ◽  
Additional Contribution ◽  
X Ray ◽  
Coordination Numbers ◽  
X Ray Absorption ◽  
Exafs Spectra

AbstractAmorphous Co100-xPx foils in the concentration range 13.4 ≤ x ≤ 26 were produced by electrodeposition. The extended X-ray absorption fine structure (EXAFS) at the phosphorous K-edge was measured in transmission mode. The phase shift was determined from the EXAFS spectrum of a crystalline Co2P reference sample. The EXAFS spectra of the amorphous Co-P alloys are characterized mainly by one single contribution from a shell of Co-atoms at a distance of 2.3 Å around the P-atoms. A small additional contribution at a shorter distance of 2.0 Å may be a hint on some direct P-P neighbours. The evaluation of reliable coordination numbers from the EXAFS spectra of the amorphous alloys is not possible.

scholarly journals Determination of Chromium(VI) Reduction by Acinetobacter haemolyticus using X-ray Absorption Fine Structure Spectroscopy

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Quek Hsiao Pei ◽  
Shafinaz Shahir ◽  
Liu Tao ◽  
Wan Azlina Ahmad
Keyword(s):  
Fine Structure ◽  
Enzymatic Reactions ◽  
Edge Structure ◽  
X Ray ◽  
Xafs Spectroscopy ◽  
Absorption Fine ◽  
Chromium Vi ◽  
X Ray Absorption ◽  
Acinetobacter Haemolyticus ◽  
Exafs Spectra

Several types of microorganisms have been reported to reduce Cr(VI) to the less toxic Cr(III) via enzymatic reactions. The main purpose of this study is to determine the reduction of Cr(VI) by a locally isolated bacterium, Acinetobacter haemolyticus (A. haemolyticus) using the x-ray absorption fine structure (XAFS) spectroscopy. XAFS analysis consisted of both the x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectra. XANES spectra of the rinsed Cr(VI)-laden A. haemolyticus biomass indicated that chromium was only present in the form of Cr (III). The nearest atoms coordinated to Cr(III) were oxygens in an octahedral geometry. The longer Cr-O bond lengths (~1.97 Å) obtained from the EXAFS spectra corroborated the presence of chromium as Cr(III) bonded to oxygen. These findings demonstrate the ability of A. haemolyticus to reduce Cr(VI) to Cr(III) that was bound to oxygen atoms of the ligands in A. haemolyticus.

scholarly journals Modulated excitation extended X-ray absorption fine structure spectroscopy

2015 ◽  
Vol 17 (16) ◽  
pp. 10579-10591 ◽  
Author(s):  
Gian Luca Chiarello ◽  
Davide Ferri
Keyword(s):  
Fine Structure ◽  
Sensitive Detection ◽  
Time Resolved ◽  
X Ray ◽  
Experimental Time ◽  
Absorption Fine ◽  
Phase Sensitive ◽  
Phase Sensitive Detection ◽  
X Ray Absorption ◽  
Exafs Spectra

Modulated excitation improves the sensitivity of EXAFS by phase sensitive detection as demonstrated by simulated and experimental time-resolved FT-EXAFS spectra.

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