High-accuracy X-ray absorption spectra from mMsolutions of nickel (II) complexes with multiple solutions using transmission XAS

A new approach is introduced for determining X-ray absorption spectroscopy (XAS) spectra on absolute and relative scales using multiple solutions with different concentrations by the characterization and correction of experimental systematics. This hybrid technique is a development of standard X-ray absorption fine structure (XAFS) along the lines of the high-accuracy X-ray extended range technique (XERT) but with applicability to solutions, dilute systems and cold cell environments. This methodology has been applied to determining absolute XAS of bis(N-n-propyl-salicylaldiminato) nickel(II) and bis(N-i-propyl-salicylaldiminato) nickel(II) complexes with square planar and tetrahedral structures in 15 mMand 1.5 mMdilute solutions. It is demonstrated that transmission XAS from dilute systems can provide excellent X-ray absorption near-edge structure (XANES) and XAFS spectra, and that transmission measurements can provide accurate measurement of subtle differences including coordination geometries. For the first time, (transmission) XAS of the isomers have been determined from low-concentration solutions on an absolute scale with a 1–5% accuracy, and with relative precision of 0.1% to 0.2% in the active XANES and XAFS regions after inclusion of systematic corrections.

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Extended X-ray absorption fine structure and multiple-scattering simulation of nickel dithiolene complexes Ni[S2C2(CF3)2]2n(n= −2, −1, 0) and an olefin adduct Ni[S2C2(CF3)2]2(1-hexene)

Journal of Synchrotron Radiation ◽

10.1107/s1600577514025041 ◽

2015 ◽

Vol 22 (1) ◽

pp. 124-129 ◽

Cited By ~ 4

Author(s):

Weiwei Gu ◽

Hongxin Wang ◽

Kun Wang

Keyword(s):

Fine Structure ◽

Multiple Scattering ◽

Edge Structure ◽

X Ray ◽

Absorption Fine ◽

Square Planar ◽

Square Planar Complexes ◽

Uv Visible ◽

Edge Features ◽

X Ray Absorption

A series of Ni dithiolene complexes Ni[S2C2(CF3)]2n(n= −2, −1, 0) (1,2,3) and a 1-hexene adduct Ni[S2C2(CF3)2]2(C6H12) (4) have been examined by NiK-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopies. Ni XANES for1–3reveals clear pre-edge features and approximately +0.7 eV shift in the NiK-edge position for `one-electron' oxidation. EXAFS simulation shows that the Ni—S bond distances for1,2and3(2.11–2.16 Å) are within the typical values for square planar complexes and decrease by ∼0.022 Å for each `one-electron' oxidation. The changes in NiK-edge energy positions and Ni—S distances are consistent with the `non-innocent' character of the dithiolene ligand. The Ni—C interactions at ∼3.0 Å are analyzed and the multiple-scattering parameters are also determined, leading to a better simulation for the overall EXAFS spectra. The 1-hexene adduct4presents no pre-edge feature, and its NiK-edge position shifts by −0.8 eV in comparison with its starting dithiolene complex3. Consistently, EXAFS also showed that the Ni—S distances in4elongate by ∼0.046 Å in comparison with3. The evidence confirms that the neutral complex is `reduced' upon addition of olefin, presumably by olefin donating the π-electron density to the LUMO of3as suggested by UV/visible spectroscopy in the literature.

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Local and electronic structure around Ga in CdTe: evidence of DX- and A-centers

Journal of Synchrotron Radiation ◽

10.1107/s0909049512042197 ◽

2012 ◽

Vol 20 (1) ◽

pp. 166-171

Author(s):

Vasil Koteski ◽

Jelena Belošević-Čavor ◽

Petro Fochuk ◽

Heinz-Eberhard Mahnke

Keyword(s):

Density Functional ◽

Plane Waves ◽

Lattice Relaxation ◽

Defect Structures ◽

Functional Theory ◽

Edge Structure ◽

X Ray ◽

First Time ◽

X Ray Absorption ◽

Good Agreement

The lattice relaxation around Ga in CdTe is investigated by means of extended X-ray absorption spectroscopy (EXAFS) and density functional theory (DFT) calculations using the linear augmented plane waves plus local orbitals (LAPW+lo) method. In addition to the substitutional position, the calculations are performed for DX- and A-centers of Ga in CdTe. The results of the calculations are in good agreement with the experimental data, as obtained from EXAFS and X-ray absorption near-edge structure (XANES). They allow the experimental identification of several defect structures in CdTe. In particular, direct experimental evidence for the existence of DX-centers in CdTe is provided, and for the first time the local bond lengths of this defect are measured directly.

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A Xanes Study of Square Copper(II) Complexes

Advances in X-ray Analysis ◽

10.1154/s0376030800013380 ◽

1991 ◽

Vol 35 (B) ◽

pp. 1115-1120

Author(s):

Hisanobu Wakita ◽

Toshio Yamaguchi ◽

Hirohiko Adachi ◽

Manabu Fujiwara ◽

Seiichi Yamashita

Keyword(s):

Aqueous Solution ◽

Lower Energy ◽

Molecular Orbital Calculations ◽

Counter Anion ◽

Edge Structure ◽

X Ray ◽

Square Planar ◽

Tetraaza Macrocycles ◽

X Ray Absorption ◽

Back Donation

AbstractThe XANES (X-ray absorption near edge structure) spectra of copper(II) ions in solid state and in solution of the square-planar copper(II) complexes with tetraaza macrocycles were measured. The peaks in the measured XANES spectra shifted to lower energy side with increasing the electron density of central copper(II) ions. The molecular orbital calculations for the complexes were carried out by the DV-Xα method, and the theoretical XANES spectra were estimated. The clear chemical shift obtained by this XANES study is evaluated and leads to a new concept of π-back donation between the copper(II) complexes and counter anion in aqueous solution.

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XANES Measurements for Studies of Adsorbed Protein Layers at Liquid Interfaces

Materials ◽

10.3390/ma13204635 ◽

2020 ◽

Vol 13 (20) ◽

pp. 4635

Author(s):

Oleg V. Konovalov ◽

Natalia N. Novikova ◽

Mikhail V. Kovalchuk ◽

Galina E. Yalovega ◽

Alexey F. Topunov ◽

...

Keyword(s):

Metal Binding ◽

Radiation Condition ◽

Liquid Interfaces ◽

Radiation Load ◽

Edge Structure ◽

Site Structure ◽

X Ray ◽

Zinc Coordination ◽

First Time ◽

X Ray Absorption

X-ray absorption near edge structure (XANES) spectra for protein layers adsorbed at liquid interfaces in a Langmuir trough have been recorded for the first time. We studied the parkin protein (so-called E3 ubiquitin ligase), which plays an important role in pathogenesis of Parkinson disease. Parkin contains eight Zn binding sites, consisting of cysteine and histidine residues in a tetracoordinated geometry. Zn K-edge XANES spectra were collected in the following two series: under mild radiation condition of measurements (short exposition time) and with high X-ray radiation load. XANES fingerprint analysis was applied to obtain information on ligand environments around zinc ions. Two types of zinc coordination geometry were identified depending on X-ray radiation load. We found that, under mild conditions, local zinc environment in our parkin preparations was very similar to that identified in hemoglobin, treated with a solution of ZnCl2 salt. Under high X-ray radiation load, considerable changes in the zinc site structure were observed; local zinc environment appeared to be almost identical to that defined in Zn-containing enzyme alkaline phosphatase. The formation of a similar metal site in unrelated protein molecules, observed in our experiments, highlights the significance of metal binding templates as essential structural modules in protein macromolecules.

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Mo coordination and Thermal Stability of the Mo–Si3N4 Absorbers for Solar Selective Coatings

MRS Advances ◽

10.1557/adv.2017.408 ◽

2017 ◽

Vol 2 (53) ◽

pp. 3061-3068 ◽

Cited By ~ 2

Author(s):

C. Prieto ◽

E. Céspedes ◽

D. Hernández-Pinilla ◽

A. Rodríguez-Palomo ◽

O. Sánchez ◽

...

Keyword(s):

Concentrated Solar Power ◽

Edge Structure ◽

X Ray ◽

Practical Applications ◽

Design And Optimization ◽

Structural Correlation ◽

First Time ◽

X Ray Absorption ◽

Optical Behavior ◽

Thermal Stability Of

ABSTRACTThe study of the chemical stability of solar selective coatings (SSC) for concentrated solar power (CSP) becomes essential for their use at high temperatures. In this paper, the short range order around Mo in Mo-Si3N4 cermets is studied for the first time by X-ray absorption spectroscopy. The information obtained by extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopies gives new insights of the origin of the optical behavior of the cermets cermets after vacuum and air annealing treatments. The established optical and structural correlation becomes of great importance for the design and optimization of SSC for practical applications.

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Interplay between Local Electronic Structure, Crystalline Structure and Magnetic Ordering in Intermetallic Compounds Ce2Fe17−xMnx

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.190.251 ◽

2012 ◽

Vol 190 ◽

pp. 251-254 ◽

Cited By ~ 1

Author(s):

Alexander A. Yaroslavtsev ◽

Alexey P. Menushenkov ◽

Olga V. Grishina ◽

Roman V. Chernikov ◽

Anatoly G. Kuchin

Keyword(s):

Crystalline Structure ◽

Magnetic Ordering ◽

Local Environment ◽

Edge Structure ◽

X Ray ◽

Local Electronic Structure ◽

Magnetic States ◽

First Time ◽

X Ray Absorption ◽

Mn Concentration

For the first time the rearrangement of cerium local environment in Ce2Fe17-xMnx(x = 0; 1; 2) intermetallics vs. Mn concentration and temperature was investigated by thespectroscopy of extended X-ray absorption fine structure (EXAFS) above K-Ce absorptionedge. At the same time under similar conditions by the spectroscopy of X-ray absorption near-edge structure (XANES) above L3-Ce absorption edge the valence state of Ce was studied. Thecorrelation is found between changes in local electronic and crystalline structure observed inCe2Fe17-xMnx and the types of magnetic states in these compounds.

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X-Ray Absorption Near Edge Structure Study and DV-Xα Calculations on Some Square-planar Copper(II) Complexes with Macrocyclic Ligands

Advances in Quantum Chemistry ◽

10.1016/s0065-3276(08)60278-6 ◽

1998 ◽

pp. 357-371 ◽

Cited By ~ 3

Author(s):

Seiichi Yamashita ◽

Manabu Fujiwara ◽

Yuko Kato ◽

Toshio Yamaguchi ◽

Hisanobu Wakita ◽

...

Keyword(s):

Structure Study ◽

Macrocyclic Ligands ◽

Edge Structure ◽

X Ray ◽

Square Planar ◽

X Ray Absorption

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In situ X-ray absorption near edge structure studies and charge transfer kinetics of Na6[V10O28] electrodes

Physical Chemistry Chemical Physics ◽

10.1039/c6cp05768c ◽

2017 ◽

Vol 19 (4) ◽

pp. 3358-3365 ◽

Cited By ~ 14

Author(s):

Han-Yi Chen ◽

Jochen Friedl ◽

Chun-Jern Pan ◽

Ali Haider ◽

Rami Al-Oweini ◽

...

Keyword(s):

Electron Transfer ◽

Charge Transfer ◽

Absorption Spectroscopy ◽

Edge Structure ◽

X Ray ◽

First Time ◽

X Ray Absorption ◽

Kinetics Of

The electron transfer of Na6[V10O28] was investigated byin situV K-edge X-ray absorption spectroscopy and chronoamperometric experiments for the first time.

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Chemical and orientational imaging of polymeric samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168074 ◽

1994 ◽

Vol 52 ◽

pp. 68-69

Author(s):

H. Ade ◽

B. Hsiao ◽

G. Mitchell ◽

E. Rightor ◽

A. P. Smith ◽

...

Keyword(s):

Ethylene Terephthalate ◽

National Laboratory ◽

Brookhaven National Laboratory ◽

Carbonyl Groups ◽

Aromatic Rings ◽

Edge Structure ◽

X Ray ◽

Scanning Transmission ◽

Polymeric Samples ◽

X Ray Absorption

We have used the Scanning Transmission X-ray Microscope at beamline X1A (X1-STXM) at Brookhaven National Laboratory (BNL) to acquire high resolution, chemical and orientation sensitive images of polymeric samples as well as point spectra from 0.1 μm areas. This sensitivity is achieved by exploiting the X-ray Absorption Near Edge Structure (XANES) of the carbon K edge. One of the most illustrative example of the chemical sensitivity achievable is provided by images of a polycarbonate/pol(ethylene terephthalate) (70/30 PC/PET) blend. Contrast reversal at high overall contrast is observed between images acquired at 285.36 and 285.69 eV (Fig. 1). Contrast in these images is achieved by exploring subtle differences between resonances associated with the π bonds (sp hybridization) of the aromatic groups of each polymer. PET has a split peak associated with these aromatic groups, due to the proximity of its carbonyl groups to its aromatic rings, whereas PC has only a single peak.

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