scholarly journals Using synchrotron radiation to study iron phases in Saharan dust samples from Athens skies

2019 ◽  
Vol 21 ◽  
pp. 136
Author(s):  
N. Chatzikonstantinou ◽  
T. J. Mertzimekis ◽  
A. Godelitsas ◽  
P. Gamaletsos ◽  
P. Nastos ◽  
...  
Keyword(s):  
Spectroscopic Technique ◽  
Saharan Dust ◽  
Environmental Research ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Environmental Research Laboratory ◽  
Short Time ◽  
X Ray Absorption ◽  
The Waves ◽  
Of Greece

The Sahara desert is the largest source of dust in the world. Saharan dust is characterized by great com- plexity, composed mainly of mixtures of mineral phases (amorphous or crystalline, with particle sizes of the order of μm or even nm). The presence of amorphous components makes it difficult to detect their struc- ture. For this purpose the spectroscopic technique of X–ray absorption fine structure μ–XAFS combined to ultrabright synchrotron SR microbeams is suitable. SR’s main advantage is the recording of spectra in a very short time. In this paper we focus on the study of forms of iron deposited on southeast Mediterranean Sea and mainland of Greece by the waves of Saharan dust. Data collection was carried out at the premises of ANKA (KIT, Germany) on the beamline SUL–X of the environmental research laboratory with advanced X–ray spectroscopic techniques, μ–XRF, μ–XRD and μ–XAFS. Results from the measurements and the simulated spectrum are presented.

scholarly journals Development of an experimental apparatus to observe ultrafast phenomena by tender X-ray absorption spectroscopy at PAL-XFEL

2022 ◽  
Vol 29 (1) ◽  
Author(s):  
Yujin Kim ◽  
Daewoong Nam ◽  
Rory Ma ◽  
Sangsoo Kim ◽  
Myung-jin Kim ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Spectroscopic Technique ◽  
Ultrafast Dynamics ◽  
Electronic Information ◽  
Time Resolved ◽  
X Ray ◽  
Experimental Apparatus ◽  
Technical Achievement ◽  
X Ray Absorption ◽  
Pal Xfel

Understanding the ultrafast dynamics of molecules is of fundamental importance. Time-resolved X-ray absorption spectroscopy (TR-XAS) is a powerful spectroscopic technique for unveiling the time-dependent structural and electronic information of molecules that has been widely applied in various fields. Herein, the design and technical achievement of a newly developed experimental apparatus for TR-XAS measurements in the tender X-ray range with X-ray free-electron lasers (XFELs) at the Pohang Accelerator Laboratory XFEL (PAL-XFEL) are described. Femtosecond TR-XAS measurements were conducted at the Ru L 3-edge of well known photosensitizer tris(bipyridine)ruthenium(II) chloride ([Ru(bpy)3]2+) in water. The results indicate ultrafast photoinduced electron transfer from the Ru center to the ligand, which demonstrates that the newly designed setup is applicable for monitoring ultrafast reactions in the femtosecond domain.

scholarly journals Iron Speciation of Natural and Anthropogenic Dust by Spectroscopic and Chemical Methods

Atmosphere ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 8 ◽  
Author(s):  
Chiara Petroselli ◽  
Beatrice Moroni ◽  
Stefano Crocchianti ◽  
Roberta Selvaggi ◽  
Riccardo Vivani ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Steel Production ◽  
Insoluble Fraction ◽  
Saharan Dust ◽  
Test Results ◽  
Chemical Methods ◽  
X Ray ◽  
Different Types ◽  
Leaching Experiments ◽  
X Ray Absorption

In this work, we have characterized the iron local structure in samples of two different types of atmospheric dust using X-ray absorption spectroscopy and selective leaching experiments. Specifically, we have investigated samples of long-range transported Saharan dust and freshly emitted steel plant fumes with the aim of individuating possible fingerprints of iron in the two cases. Findings include (1) prevalence of octahedral coordinated Fe 3 + for all samples; (2) presence of 6-fold coordinated Fe 3 + , aluminosilicates and iron oxy(hydr)oxides in Saharan dust and (3) of Fe-bearing spinel-like structures in the industrial fumes; (4) general predominance of the residual insoluble fraction with a notable difference: 69% for Saharan dust and 93% for steel production emissions, associated with aluminosilicates and non-reducible iron oxy(hydr)oxides, and Fe spinels, respectively. The remarkable differences between the X-ray absorption spectroscopy (XAS) spectra and leaching test results for the two sample types suggest the possibility to exploit the present approach in more complex cases. To this aim, two additional case studies of mixed aerosol samples are presented and discussed.

scholarly journals Iron Speciation in Different Saharan Dust Advections and Effect of the Procedural Blank on the Results From X-ray Absorption Spectroscopy and Selective Leaching Experiments

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 735
Author(s):  
Chiara Petroselli ◽  
Beatrice Moroni ◽  
Stefano Crocchianti ◽  
Roberta Selvaggi ◽  
Francesco Soggia ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Saharan Dust ◽  
Residual Fraction ◽  
Selective Leaching ◽  
Iron Speciation ◽  
X Ray ◽  
Fe Speciation ◽  
Leaching Experiments ◽  
X Ray Absorption

In this work, we applied X-ray Absorption Spectroscopy (XAS) and selective leaching experiments for investigating iron speciation in different dust advections collected on different unwashed quartz fiber filters. XAS analysis evidenced a predominance of Fe(III) in 6-fold coordination for Saharan dust and a trend towards Fe(II) and 4-fold coordination in the order: Saharan dust, mixed Saharan, and non-Saharan aerosol samples. The role of the sampling substrate was evaluated explicitly, including in the analysis a set of blank filters. We were able to pinpoint the possible contribution to the overall XAS spectrum of the residual Fe on quartz as the concentration decrease towards the blank value. In particular, the filter substrate showed a negligible effect on the structural trend mentioned above. Furthermore, selective leaching experiments evidenced a predominance of the residual fraction on Fe speciation and indicated the lowest Fe concentrations for which the blank contribution is <20% are 1 μ g for the first three steps of the procedure (releasing the acid-labile, reducible and oxidizable phases, respectively) and 10 μ g for the last step (dissolving the insoluble residuals).

Assessing nickel oxide electrocatalysts incorporating diamines and having improved oxygen evolution activity using operando UV/visible and X-ray absorption spectroscopy

2021 ◽  
Author(s):  
Takafumi Miura ◽  
Shun Tsunekawa ◽  
Sho Onishi ◽  
Toshiaki Ina ◽  
Kehsuan Wang ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Absorption Spectroscopy ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Uv Visible ◽  
X Ray Absorption

The role of diamines incorporated in a nickel oxide electrocatalyst for water splitting was examined using operando UV/XAFS spectroscopic techniques.

Spectroscopic Characterization of the Nitridation Process of Polymeric Precursors to SI-M-N-O Systems (M=Ti, Zr, Al)

1992 ◽  
Vol 287 ◽  
Author(s):  
F. Babonneau ◽  
G. D. Soraru
Keyword(s):  
Spectroscopic Characterization ◽  
Ceramic Materials ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Nitridation Process ◽  
Local Environments ◽  
Ceramic Precursors ◽  
Mixed Ceramic ◽  
X Ray Absorption

ABSTRACTA commercial polycarbosilane was modified with various metallic alkoxides to get mixed ceramic precursors in the Si-M-C-O systems (M=Ti, Zr Al). Pyrolysis under ammonia leads to the formation of various ceramic materials depending on the nature of M : Si3N4/TiN, Si3N4/ZrO2 or β′-SiAlON phases.The polymer-to-ceramics conversion have been studied by MAS-NMR (29 Si, 27Al) and X-ray absorption (Ti K-edge). This paper will show how these two complementary spectroscopic techniques can be used to follow the nitridation process by probing local environments of different elements. In addition, it will be pointed out how X-ray absorption can be a powerful tool for the detection of the crystallization of nitride cubic phases.

scholarly journals Synchrotron Radiation Spectroscopic Techniques as Tools for the Medicinal Chemist: Microprobe X-Ray Fluorescence Imaging, X-Ray Absorption Spectroscopy, and Infrared Microspectroscopy

2012 ◽  
Vol 65 (3) ◽  
pp. 204 ◽  
Author(s):  
Carolyn Therese Dillon
Keyword(s):  
Synchrotron Radiation ◽  
Fluorescence Spectroscopy ◽  
Absorption Spectroscopy ◽  
Therapeutic Agents ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Infrared Microspectroscopy ◽  
Radiation Sources ◽  
Synchrotron Radiation Techniques ◽  
X Ray Absorption

This review updates the recent advances and applications of three prominent synchrotron radiation techniques, microprobe X-ray fluorescence spectroscopy/imaging, X-ray absorption spectroscopy, and infrared microspectroscopy, and highlights how these tools are useful to the medicinal chemist. A brief description of the principles of the techniques is given with emphasis on the advantages of using synchrotron radiation-based instrumentation rather than instruments using typical laboratory radiation sources. This review focuses on several recent applications of these techniques to solve inorganic medicinal chemistry problems, focusing on studies of cellular uptake, distribution, and biotransformation of established and potential therapeutic agents. The importance of using these synchrotron-based techniques to assist the development of, or validate the chemistry behind, drug design is discussed.

scholarly journals Development of in situ soft X-ray absorption spectroscopic technique under high temperature and controlled atmosphere

2014 ◽  
Vol 262 ◽  
pp. 911-913 ◽  
Author(s):  
Ryo Oike ◽  
Koji Amezawa ◽  
Takashi Nakamura ◽  
Yusuke Tamenori ◽  
Keiji Yashiro ◽  
...  
Keyword(s):  
High Temperature ◽  
Spectroscopic Technique ◽  
Controlled Atmosphere ◽  
X Ray ◽  
X Ray Absorption

Structure of Glasses of Geological Interest: Applying Spectroscopic Techniques

MRS Bulletin ◽  
1992 ◽  
Vol 17 (5) ◽  
pp. 53-59 ◽  
Author(s):  
Frank C. Hawthorne
Keyword(s):  
High Pressures ◽  
Materials Science ◽  
Silicate Glasses ◽  
Silicate Melts ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Structure Of Glasses ◽  
Physical And Chemical ◽  
X Ray Absorption ◽  
Melt Phase

Glasses are a minor fraction of Earth materials. However, all igneous processes within the Earth involve a melt phase (magma), and our understanding of the physical and chemical features of these processes is contingent upon an adequate understanding of the melt phase itself. In particular, we wish to relate the behavior of such melts to their composition and structure in the range of physical and chemical conditions in which they occur. The physical conditions of many of these processes are particularly difficult to reproduce in the laboratory, and the ability to predict behavior under such conditions is the goal. From a geological viewpoint, the primary interest is in silicate melts because of the composition of the Earth's lithosphere and mantle. There are significant experimental difficulties in looking at the behavior of silicate melts, so much work has focused on glasses as melt analogues since spectroscopic data on silicate glasses and melts (Figure 1) are similar.Silicate glasses are also of considerable industrial interest, and early work in the geological field borrowed heavily from materials science. However, the thrust to understand natural magmas led geologically based work into more complex chemical systems (e.g., hydrous alkali-alkaline-earth-aluminosilicates) and their behavior at high pressures.The structure of glasses is a complex issue, and many different experimental techniques are needed to resolve the details of their structure. Here I will focus on the following techniques: IR (infrared), Raman, Mössbauer, EXAFS (extended x-ray absorption fine structure) and XANES (x-ray absorption near-edge spectroscopy) spectroscopies.

Time-Resolved X-Ray Absorption Spectroscopy: Strengths and Limitations

1988 ◽  
Vol 143 ◽  
Author(s):  
A. Fontaine ◽  
E. Dartyge ◽  
J. P. Itie ◽  
A. Jucha ◽  
A. Polian ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Materials Science ◽  
Energy Scale ◽  
Time Resolved ◽  
Decay Channels ◽  
X Ray ◽  
Exact Shape ◽  
Full Benefit ◽  
Short Time ◽  
X Ray Absorption

AbstractX-ray Absorption Spectroscopy has proved to be a powerful tool to elucidate a huge number of questions in materials science. Great interest exists in time-resolved experiments achieved with extreme energy resolution and energy scale stability to take a full benefit of the strong correlation between the stereochemical environment of the absorbing atom and the exact shape and position of the absorption edge.Fast energy dispersive X-ray spectroscopy allows in-situ observations with data collected in a short time. Nowadays the main limitation concerns very low-concentration samples since It is no longer possible to use the dispersive geometry because detection of the signal via the decay channels is no more possible.

scholarly journals The effect of orbital-lattice coupling on the electrical resistivity of YBaCuFeO5 investigated by X-ray absorption

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
M. K. Srivastava ◽  
X.-S. Qiu ◽  
Y. Y. Chin ◽  
S. H. Hsieh ◽  
Y. C. Shao ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Single Crystal ◽  
Nearest Neighbor ◽  
Linear Dichroism ◽  
Close Correlation ◽  
Waller Factor ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
X Ray Absorption

AbstractTemperature-dependent X-ray absorption near-edge structures, X-ray linear dichroism (XLD) and extended X-ray absorption fine structure (EXAFS) spectroscopic techniques were used to investigate the valence state, preferred orbital and local atomic structure that significantly affect the electrical and magnetic properties of a single crystal of YBaCuFeO5 (YBCFO). An onset of increase of resistivity at ~180 K, followed by a rapid increase at/below 125 K, is observed. An antiferromagnetic (AFM)-like transition is close to the temperature at which the resistivity starts to increase in the ab-plane and is also observed with strong anisotropy between the ab-plane and the c-axis. The XLD spectra at the Fe L3,2-edge revealed a change in Fe 3d eg holes from the preferential $${\bf{3}}{{\boldsymbol{d}}}_{{{\bf{x}}}^{{\bf{2}}}{\boldsymbol{-}}{{\bf{y}}}^{{\bf{2}}}}$$3dx2−y2 orbital at high temperature (300–150 K) to the $${\bf{3}}{{\boldsymbol{d}}}_{{{\bf{3}}{\bf{z}}}^{{\bf{2}}}{\boldsymbol{-}}{{\bf{r}}}^{{\bf{2}}}}$$3d3z2−r2 orbital at/below 125 K. The analysis of the Fe K-edge EXAFS data of YBCFO further revealed an unusual increase in the Debye-Waller factor of the nearest-neighbor Fe-O bond length at/below 125 K, suggesting phonon-softening behavior, resulting in the breaking of lattice symmetry, particularly in the ab-plane of Fe-related square pyramids. These findings demonstrate a close correlation between electrical resistivity and coupling of the preferred Fe 3d orbital with lattice distortion of a single crystal of YBCFO.

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