The structure and bonding properties of tiopronin-protected silver nanoparticles as studied by X-ray absorption spectroscopy

2018 ◽  
Vol 96 (7) ◽  
pp. 749-754 ◽  
Author(s):  
J. Daniel Padmos ◽  
David J. Morris ◽  
Peng Zhang
Keyword(s):  
Optical Properties ◽  
Absorption Spectroscopy ◽  
Structural Changes ◽  
Chemical Properties ◽  
Structure Property ◽  
Ag Nps ◽  
X Ray ◽  
Ligand Shell ◽  
Bonding Properties ◽  
X Ray Absorption

Thiolate-protected Ag nanoparticles (NPs) exhibit interesting physical and chemical properties which may lead to various sensing, diagnostic, and therapeutic applications. Further, understanding structure–property relationships of Ag NPs is of great interest to optimize their application. Herein, we used TEM, UV–vis, and a series of synchrotron X-ray spectroscopy techniques to probe the local structure and chemical bonding properties of thiolate-stabilized Ag NPs. Compared with other Ag nanostructures prepared under slightly modified conditions, the Ag NPs were found to have pronounced structural changes, which led to immensely different optical properties. Notably, the NPs were also found to have similar surface structure to recently elucidated Ag nanoclusters prepared with different thiolates. These findings suggest that the NP structure and optical properties can be sensitively tailored by controlling the synthetic conditions. The multi-element, multi-core excitation approach (i.e., Ag K-, Ag L3-, and S K-edges) employed in the X-ray absorption spectroscopy measurements was also demonstrated as an effective tool to uncover the NP structure from both the metal core and the ligand shell perspectives.

Ascertaining the nanocluster formation within an ion-irradiated Pt/Ni/C multi-trilayer with X-ray absorption spectroscopy

2012 ◽  
Vol 20 (1) ◽  
pp. 137-144
Author(s):  
Nitya Ramanan ◽  
Sumalay Roy ◽  
Debdutta Lahiri ◽  
Surinder M. Sharma ◽  
B. N. Dev
Keyword(s):  
Absorption Spectroscopy ◽  
Structural Changes ◽  
Nearest Neighbor ◽  
Ion Irradiation ◽  
Physical Adsorption ◽  
X Ray ◽  
Bimetallic Nanoclusters ◽  
Wave Technique ◽  
Wide Scale ◽  
X Ray Absorption

In this work nanoclusters formed in a Pt/Ni/C multi-trilayer by the ion-irradiated method of synthesis are characterized. In particular, an attempt to understand the role of interfaces in the synthesis is made. With this objective, ion-irradiation-induced structural changes in a Pt/Ni/C multi-trilayer using X-ray absorption spectroscopy (at the NiK-edge) in conjunction with the X-ray standing-wave technique are investigated. The XANES analysis identifies chemical binding at pristine Ni/C and Ni/Pt interfaces, in contrast with physical adsorption at the Pt/C interface. The chemical nature of the interfaces determines their relative stability with respect to irradiation and controls the extent of metallic diffusion. The most interesting structural change, upon irradiation, is the disruption of the Pt/C interface and subsequent migration of Pt atoms towards pre-diffused Ni atoms within the C layer, leading to the formation of Ni-centered Ni–Pt bimetallic nanoclusters (with Ni:Pt = 60:40). These clusters are highly disordered beyond their nearest neighbor and find wide-scale applications as, for example, magnetic devicesetc. The implications of these findings on the design goals are discussed.

X-ray absorption spectroscopy and density functional analysis of the Fe3+ distribution profile on Al sites in a chrysoberyl crystal, BeAl2O4:Fe3+

2016 ◽  
Vol 49 (2) ◽  
pp. 385-388 ◽  
Author(s):  
Kanokwan Kanchiang ◽  
Atipong Bootchanont ◽  
Janyaporn Witthayarat ◽  
Sittichain Pramchu ◽  
Panjawan Thanasuthipitak ◽  
...  
Keyword(s):  
Optical Properties ◽  
Absorption Spectroscopy ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Distribution Profile ◽  
Laser Applications ◽  
Edge Structure ◽  
X Ray ◽  
Site Distribution ◽  
X Ray Absorption

Chrysoberyl is one of the most interesting minerals for laser applications, widely used for medical purposes, as it exhibits higher laser performance than other materials. Although its utilization has been vastly expanded, the location of transition metal impurities, especially the iron that is responsible for chrysoberyl's special optical properties, is not completely understood. The full understanding and control of these optical properties necessitates knowledge of the precise location of the transition metals inside the structure. Therefore, synchrotron X-ray absorption spectroscopy (XAS), a local structural probe sensitive to the different local geometries, was employed in this work to determine the site occupation of the Fe3+ cation in the chrysoberyl structure. An Fe K-edge X-ray absorption near-edge structure (XANES) simulation was performed in combination with density functional theory calculations of Fe3+ cations located at different locations in the chrysoberyl structure. The simulated spectra were then qualitatively compared with the measured XANES features. The comparison indicates that Fe3+ is substituted on the two different Al2+ octahedral sites with the proportion 60% on the inversion site and 40% on the reflection site. The accurate site distribution of Fe3+ obtained from this work provides useful information on the doping process for improving the efficiency of chrysoberyl as a solid-state laser material.

scholarly journals A zone-plate-based two-color spectrometer for indirect X-ray absorption spectroscopy

2019 ◽  
Vol 26 (4) ◽  
pp. 1266-1271 ◽  
Author(s):  
Florian Döring ◽  
Marcel Risch ◽  
Benedikt Rösner ◽  
Martin Beye ◽  
Philipp Busse ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Fresnel Zone ◽  
Decay Channel ◽  
Chemical Properties ◽  
Fluorescence Yield ◽  
Complex Materials ◽  
X Ray ◽  
Total Fluorescence ◽  
X Ray Absorption

X-ray absorption spectroscopy (XAS) is a powerful element-specific technique that allows the study of structural and chemical properties of matter. Often an indirect method is used to access the X-ray absorption (XA). This work demonstrates a new XAS implementation that is based on off-axis transmission Fresnel zone plates to obtain the XA spectrum of La0.6Sr0.4MnO3 by analysis of three emission lines simultaneously at the detector, namely the O 2p–1s, Mn 3s–2p and Mn 3d–2p transitions. This scheme allows the simultaneous measurement of an integrated total fluorescence yield and the partial fluorescence yields (PFY) of the Mn 3s–2p and Mn 3d–2p transitions when scanning the Mn L-edge. In addition to this, the reduction in O fluorescence provides another measure for absorption often referred to as the inverse partial fluorescence yield (IPFY). Among these different methods to measure XA, the Mn 3s PFY and IPFY deviate the least from the true XA spectra due to the negligible influence of selection rules on the decay channel. Other advantages of this new scheme are the potential to strongly increase the efficiency and throughput compared with similar measurements using conventional gratings and to increase the signal-to-noise of the XA spectra as compared with a photodiode. The ability to record undistorted bulk XA spectra at high flux is crucial for future in situ spectroscopy experiments on complex materials.

Local electronic and atomic structures of the mixed B-site ions in SrFe1−xMnxO3−δ studied with X-ray absorption spectroscopy

2021 ◽  
pp. 2140048
Author(s):  
Masatsugu Oishi ◽  
Fumito Fujishiro ◽  
Toshiaki Ina ◽  
Hirona Yamagishi ◽  
Iwao Watanabe ◽  
...  
Keyword(s):  
Fine Structure ◽  
Absorption Spectroscopy ◽  
Structural Changes ◽  
Perovskite Oxides ◽  
X Ray ◽  
Atomic Structures ◽  
Exafs Analysis ◽  
Mn Content ◽  
X Ray Absorption ◽  
Fe Ions

Local electronic and atomic structures of the B-site ions in perovskite SrFe[Formula: see text]Mn[Formula: see text]O[Formula: see text] were evaluated with X-ray absorption spectroscopy (XAS) at Mn, Fe [Formula: see text]- and [Formula: see text]-edges and O [Formula: see text]-edge. The energy of [Formula: see text]- and [Formula: see text]-edge peaks for Mn and Fe ions stayed unchanged against the change in Mn content [Formula: see text]. The analysis of Mn [Formula: see text]-edge extended X-ray absorption fine structure (EXAFS) revealed that Mn−O polyhedra was kept as an octahedron with Mn[Formula: see text] irrespective of the [Formula: see text] value, agreeing with the results of [Formula: see text]-edge spectra. The Fe [Formula: see text]-edge EXAFS analysis showed that the Fe–O distance decreased with decrease of the Mn contents, suggesting that the ratio of FeO5 polyhedra to FeO6 octahedra is increased due to smaller oxygen amount. By analyzing both the [Formula: see text]-edge and [Formula: see text]-edge spectra, we clarified the local electronic and atomic structural changes particularly occurred in the B-site mixed perovskite oxides.

Investigation of Local Structures Around Luminescent Centers in Doped Nanocrystal Phosphors

1995 ◽  
Vol 405 ◽  
Author(s):  
Y. L. Soo ◽  
S. W. Huang ◽  
Z. H. Ming ◽  
Y. H. Kao ◽  
E. Goldburt ◽  
...  
Keyword(s):  
Optical Properties ◽  
Structural Changes ◽  
Structural Information ◽  
The Novel ◽  
X Ray ◽  
Local Structures ◽  
Size Dependent ◽  
Luminescent Centers ◽  
X Ray Absorption ◽  
Mn Doped

AbstractExtended x-ray absorption fine structure (EXAFS) technique has been employed to investigate the local structures around luminescent centers in nanocrystals of Mn-doped ZnS and Tb-doped Y2O3. Size-dependent local structural changes around Mn luminescent centers have been found in Mn-doped nanocrystals of ZnS by using Mn K-edge EXAFS. Local structures around Tb investigated by Tb Li-edge EXAFS also show substantial differences between bulk and nanocrystal samples. This structural information is useful for understanding the novel optical properties of doped nanocrystals.

scholarly journals Pressure-induced structural changes in α-MoO3 probed by X-ray absorption spectroscopy

2019 ◽  
Vol 503 ◽  
pp. 012018 ◽  
Author(s):  
Inga Jonane ◽  
Andris Anspoks ◽  
Lucie Nataf ◽  
Francois Baudelet ◽  
Tetsuo Irifune ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Structural Changes ◽  
X Ray ◽  
X Ray Absorption
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