Radiation chemistry of molecular compounds and polymers by soft X-ray spectroscopy and microscopy

Soft X-ray-induced radiation chemistry in selected Fe molecular compounds and some aliphatic polymers was studied using soft X-ray absorption spectroscopy, and scanning transmission X-ray microscopy. X-ray absorption near-edge structure (XANES) spectroscopy was used to elucidate the radiation chemistry. The results show that damage to the Fe molecular complexes involves Fe-ligand bond breaking, ligand damage, and subsequent photoreduction of Fe(III) if it is not tightly bonded to oxygen. Upon radiation damage, polymer PAN primarily undergoes chemical structure changes without mass loss, PECA experiences chemical structure changes as well as small mass loss, while PPC and PEC suffer large mass loss with chemical structure changes. These studies are not only important to X-ray analysis of radiation sensitive materials but also are valuable to the applications of X-ray lithography and other types of nanofabrication involving photoresist.

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Chemical Structure of TiO2Nanotube Photocatalysts Promoted by Copper and Iron

International Journal of Photoenergy ◽

10.1155/2013/243160 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 6

Author(s):

Chang-Yu Liao ◽

H. Paul Wang ◽

Hong-Ping Lin

Keyword(s):

Methylene Blue ◽

Visible Light ◽

Photocatalytic Degradation ◽

Chemical Structure ◽

Visible Light Photocatalysis ◽

Light Radiation ◽

Photoexcited Electron ◽

Edge Structure ◽

X Ray ◽

X Ray Absorption

TiO2nanotubes (TNTs) promoted by copper (5%) (Cu-TNT) and iron (5%) (Fe-TNT) were prepared for visible-light photocatalysis. By X-ray absorption near edge structure (XANES) spectroscopy, it is found that the enhanced photocatalytic degradation of methylene blue (MB) on Cu-TNT and Fe-TNT is associated with the predominant surface photoactive sites A2((Ti=O)O4). By extended X-ray absorption fine structure (EXAFS) spectroscopy, the dispersed copper and iron also cause increases in the Ti–O and Ti–(O)–Ti bond distances by 0.01-0.02 and 0.04-0.05 Å, respectively. The decreased Ti–O bonding energy may lead to an increase of photoexcited electron transport. The copper- or-iron promoted TNT can thus enhance photocatalytic degradation of MB under the visible-light radiation.

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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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In Vivo Investigation of the Distribution and the Local Speciation of Selenium inAlliumcepa L. by Means of Microscopic X-ray Absorption Near-Edge Structure Spectroscopy and Confocal Microscopic X-ray Fluorescence Analysis

Analytical Chemistry ◽

10.1021/ac060380s ◽

2006 ◽

Vol 78 (22) ◽

pp. 7616-7624 ◽

Cited By ~ 49

Author(s):

Ewa Bulska ◽

Irena A. Wysocka ◽

Małgorzata H. Wierzbicka ◽

Kristof Proost ◽

Koen Janssens ◽

...

Keyword(s):

Fluorescence Analysis ◽

Edge Structure ◽

X Ray ◽

X Ray Absorption

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Full-Field Calcium K-Edge X-ray Absorption Near-Edge Structure Spectroscopy on Cortical Bone at the Micron-Scale: Polarization Effects Reveal Mineral Orientation

Analytical Chemistry ◽

10.1021/acs.analchem.5b04898 ◽

2016 ◽

Vol 88 (7) ◽

pp. 3826-3835 ◽

Cited By ~ 12

Author(s):

Bernhard Hesse ◽

Murielle Salome ◽

Hiram Castillo-Michel ◽

Marine Cotte ◽

Barbara Fayard ◽

...

Keyword(s):

Cortical Bone ◽

Edge Structure ◽

Full Field ◽

Polarization Effects ◽

X Ray ◽

X Ray Absorption

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Local structure and cation distribution analysis of Mn1-xZnxFe2O4 powders by X-ray Absorption Near Edge Structure Spectroscopy

Radiation Physics and Chemistry ◽

10.1016/j.radphyschem.2021.109628 ◽

2021 ◽

pp. 109628

Author(s):

Jaru Jutimoosik ◽

Pinit Kidkhunthod ◽

Theerachai Bongkarn ◽

Rattikorn Yimnirun

Keyword(s):

Cation Distribution ◽

Local Structure ◽

Distribution Analysis ◽

Edge Structure ◽

X Ray ◽

X Ray Absorption

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Database of ab initio L-edge X-ray absorption near edge structure

Scientific Data ◽

10.1038/s41597-021-00936-5 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Yiming Chen ◽

Chi Chen ◽

Chen Zheng ◽

Shyam Dwaraknath ◽

Matthew K. Horton ◽

...

Keyword(s):

High Throughput ◽

Scattering Theory ◽

Research Community ◽

Metal Compounds ◽

Edge Structure ◽

X Ray ◽

Initial Release ◽

Computational Workflow ◽

X Ray Absorption

AbstractThe L-edge X-ray Absorption Near Edge Structure (XANES) is widely used in the characterization of transition metal compounds. Here, we report the development of a database of computed L-edge XANES using the multiple scattering theory-based FEFF9 code. The initial release of the database contains more than 140,000 L-edge spectra for more than 22,000 structures generated using a high-throughput computational workflow. The data is disseminated through the Materials Project and addresses a critical need for L-edge XANES spectra among the research community.

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Theoretical and experimental investigation of point defects in cubic boron nitride

MRS Advances ◽

10.1557/adv.2017.53 ◽

2017 ◽

Vol 2 (29) ◽

pp. 1545-1550 ◽

Cited By ~ 1

Author(s):

Nicholas L. McDougall ◽

Jim G. Partridge ◽

Desmond W. M. Lau ◽

Philipp Reineck ◽

Brant C. Gibson ◽

...

Keyword(s):

Boron Nitride ◽

Cubic Boron Nitride ◽

Optical Emission ◽

Wide Band ◽

Wide Band Gap ◽

Edge Structure ◽

X Ray ◽

Substitutional Defects ◽

X Ray Absorption ◽

Annealing Experiments

ABSTRACTCubic boron nitride (cBN) is a synthetic wide band gap material that has attracted attention due to its high thermal conductivity, optical transparency and optical emission. In this work, defects in cBN have been investigated using experimental and theoretical X-ray absorption near edge structure (XANES). Vacancy and O substitutional defects were considered, with O substituted at the N site (ON) to be the most energetically favorable. All defects produce unique signatures in either the B or N K-edges and can thus be identified using XANES. The calculations coupled with electron-irradiation / annealing experiments strongly suggest that ON is the dominant defect in irradiated cBN and remains after annealing. This defect is a likely source of optical emission in cBN.

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