X-Ray Absorption and RIXS on Coordination Complexes

2016 ◽  
pp. 407-435 ◽  
Author(s):  
Thomas Kroll ◽  
Marcus Lundberg ◽  
Edward I. Solomon
Keyword(s):  
Coordination Complexes ◽  
X Ray ◽  
X Ray Absorption

Molecular Characterization of Noble Metal Adsorption at the Water-Aluminum Oxide Interface

2011 ◽  
Vol 396-398 ◽  
pp. 745-750
Author(s):  
Jian Ming Liu ◽  
J. R. Regalbuto
Keyword(s):  
Noble Metal ◽  
Pollution Abatement ◽  
Coordination Complexes ◽  
Metal Adsorption ◽  
Oxide Interface ◽  
X Ray ◽  
Catalysts Preparation ◽  
X Ray Absorption ◽  
Effect Of Surface

We have obtained relatively unambiguous evidence that validates a simple, predictive model describing the uptake of noble metal coordination complexes from aqueous solutions onto oxide surfaces. The results confirm that the metal-oxide interaction is essentially electrostatic in nature. The evidence has been obtained by applying extended x-ray absorption fine structure (EXAFS) analysis to noble metal adsorption systems in which the effect of surface-localized pH has been isolated and quantified. The model has applications ranging from catalysts preparation to heavy metal pollution abatement and precious metal recovery.

Two faces of the same coin: coupling X‐ray Absorption and NMR spectroscopies to investigate the exchange reaction between prototypical Cu coordination complexes

2021 ◽  
Author(s):  
Paola D'Angelo ◽  
Daniele Del Giudice ◽  
Francesco Tavani ◽  
Marika Di Berto Mancini ◽  
Federico Frateloreto ◽  
...  
Keyword(s):  
Exchange Reaction ◽  
Coordination Complexes ◽  
X Ray ◽  
X Ray Absorption

Probing covalency in halogen bonds through donor K-edge X-ray absorption spectroscopy: polyhalides as coordination complexes

2017 ◽  
Vol 203 ◽  
pp. 79-91 ◽  
Author(s):  
Chantal L. Mustoe ◽  
Mathusan Gunabalasingam ◽  
Darren Yu ◽  
Brian O. Patrick ◽  
Pierre Kennepohl
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Absorption Spectroscopy ◽  
Coordination Complexes ◽  
Halogen Bonds ◽  
X Ray ◽  
Secondary Interactions ◽  
Coordination Bonds ◽  
X Ray Absorption ◽  
Degree Of Charge Transfer

The properties of halogen bonds (XBs) in solid-state I2X−and I4X−materials (where X = Cl, Br) are explored using donor K-edge X-ray absorption spectroscopy (XAS) to experimentally determine the degree of charge transfer in such XB interactions. The degree of covalency in these bonds is substantial, even in cases where significantly weaker secondary interactions are observed. These data, in concert with previous work in this area, suggests that certain halogen bonds have covalent contributions to bonding that are similar to, and even exceed, those observed in transition metal coordinate bonds. For this reason, we suggest that XB interactions of this type be denoted in a similar way to coordination bonds (X → Y) as opposed to using a representation that is the same as for significantly less covalent hydrogen bonds (X⋯Y).

scholarly journals Scrutinizing metal–ligand covalency and redox non-innocence via nitrogen K-edge X-ray absorption spectroscopy

2019 ◽  
Vol 10 (19) ◽  
pp. 5044-5055 ◽  
Author(s):  
James T. Lukens ◽  
Ida M. DiMucci ◽  
Takashi Kurogi ◽  
Daniel J. Mindiola ◽  
Kyle M. Lancaster
Keyword(s):  
Transition Metals ◽  
Absorption Spectroscopy ◽  
Coordination Complexes ◽  
X Ray ◽  
Inner Sphere ◽  
Aminyl Radical ◽  
X Ray Absorption ◽  
Radical Ligand ◽  
Metal Ligand

A series of nitrogen K-edge XAS data obtained for coordination complexes of diverse transition metals is used to calibrate computational pre-edge peak energies and to afford estimates of metal–ligand covalencies. The approach is extended to probe an inner-sphere aminyl radical ligand.

scholarly journals Theory and X-ray Absorption Spectroscopy for Aluminum Coordination Complexes – Al K-Edge Studies of Charge and Bonding in (BDI)Al, (BDI)AlR2, and (BDI)AlX2 Complexes

2015 ◽  
Vol 137 (32) ◽  
pp. 10304-10316 ◽  
Author(s):  
Alison B. Altman ◽  
C. D. Pemmaraju ◽  
Clément Camp ◽  
John Arnold ◽  
Stefan G. Minasian ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Coordination Complexes ◽  
X Ray ◽  
X Ray Absorption

X-ray microanalysis of thin specimens in the transmission electron microscope at voltages up to 1000 Kv.

1978 ◽  
Vol 36 (1) ◽  
pp. 540-541
Author(s):  
G. Cliff ◽  
M.J. Nasir ◽  
G.W. Lorimer ◽  
N. Ridley
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Present Series ◽  
Constant Independent ◽  
X Ray ◽  
Transmission Electron ◽  
Series Of Experiments ◽  
Image Position ◽  
X Ray Absorption

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.

SIGMAL: A Program for Calculating L-Shell lonization Cross-Sections

1981 ◽  
Vol 39 ◽  
pp. 198-199 ◽  
Author(s):  
R.F. Egerton
Keyword(s):  
Cross Sections ◽  
Fortran Program ◽  
Absorption Data ◽  
X Ray ◽  
Atomic Electrons ◽  
Energy Dependent ◽  
Hydrogenic Model ◽  
Electron Energy Loss ◽  
X Ray Absorption ◽  
Shell Ionization

SIGMAL is a short (∼ 100-line) Fortran program designed to rapidly compute cross-sections for L-shell ionization, particularly the partial crosssections required in quantitative electron energy-loss microanalysis. The program is based on a hydrogenic model, the L1 and L23 subshells being represented by scaled Coulombic wave functions, which allows the generalized oscillator strength (GOS) to be expressed analytically. In this basic form, the model predicts too large a cross-section at energies near to the ionization edge (see Fig. 1), due mainly to the fact that the screening effect of the atomic electrons is assumed constant over the L-shell region. This can be remedied by applying an energy-dependent correction to the GOS or to the effective nuclear charge, resulting in much closer agreement with experimental X-ray absorption data and with more sophisticated calculations (see Fig. 1 ).

point-Analysis Using the Extrapolation Method in the Analytical Electron microscope

1990 ◽  
Vol 48 (2) ◽  
pp. 430-431
Author(s):  
Zenji Horita ◽  
Ryuzo Nishimachi ◽  
Takeshi Sano ◽  
Minoru Nemoto
Keyword(s):  
Electron Microscope ◽  
Extrapolation Method ◽  
X Ray ◽  
Absorption Correction ◽  
Point Analysis ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Data Points ◽  
Identical Composition ◽  
X Ray Absorption

Absorption correction is often required in quantitative x-ray microanalysis of thin specimens using the analytical electron microscope. For such correction, it is convenient to use the extrapolation method[l] because the thickness, density and mass absorption coefficient are not necessary in the method. The characteristic x-ray intensities measured for the analysis are only requirement for the absorption correction. However, to achieve extrapolation, it is imperative to obtain data points more than two at different thicknesses in the identical composition. Thus, the method encounters difficulty in analyzing a region equivalent to beam size or the specimen with uniform thickness. The purpose of this study is to modify the method so that extrapolation becomes feasible in such limited conditions. Applicability of the new form is examined by using a standard sample and then it is applied to quantification of phases in a Ni-Al-W ternary alloy.The earlier equation for the extrapolation method was formulated based on the facts that the magnitude of x-ray absorption increases with increasing thickness and that the intensity of a characteristic x-ray exhibiting negligible absorption in the specimen is used as a measure of thickness.

EXELFS Studies of Carbon Fibers

1990 ◽  
Vol 48 (2) ◽  
pp. 72-73
Author(s):  
V. Serin ◽  
K. Hssein ◽  
G. Zanchi ◽  
J. Sévely
Keyword(s):  
Carbon Fibers ◽  
Energy Analysis ◽  
Electron Excitation ◽  
Complex Structures ◽  
High Modulus ◽  
Promising Technique ◽  
X Ray ◽  
Fine Structures ◽  
X Ray Absorption

The present developments of electron energy analysis in the microscopes by E.E.L.S. allow an accurate recording of the spectra and of their different complex structures associated with the inner shell electron excitation by the incident electrons (1). Among these structures, the Extended Energy Loss Fine Structures (EXELFS) are of particular interest. They are equivalent to the well known EXAFS oscillations in X-ray absorption spectroscopy. Due to the EELS characteristic, the Fourier analysis of EXELFS oscillations appears as a promising technique for the characterization of composite materials, the major constituents of which are low Z elements. Using EXELFS, we have developed a microstructural study of carbon fibers. This analysis concerns the carbon K edge, which appears in the spectra at 285 eV. The purpose of the paper is to compare the local short range order, determined by this way in the case of Courtauld HTS and P100 ex-polyacrylonitrile carbon fibers, which are high tensile strength (HTS) and high modulus (HM) fibers respectively.

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