Structure and Electronic Properties of Molecularly-capped Metal Nanoparticles: The effect of Nano-size, Metal Core and Capping Molecule Probed by X-ray Absorption Spectroscopy

2002 ◽  
Vol 738 ◽  
Author(s):  
Peng Zhang ◽  
Tsun-Kong Sham
Keyword(s):  
Fine Structure ◽  
Metal Nanoparticles ◽  
Charge Distribution ◽  
Local Structure ◽  
Structure And Properties ◽  
Metal Core ◽  
Au Nps ◽  
X Ray ◽  
X Ray Absorption ◽  
Nano Size

ABSTRACTWe have conducted an investigation using TEM, XRD and synchrotron based X-ray absorption fine structure (XAFS) to probe the structural and electronic characteristics of several molecularly capped metal nanoparticles (NPs). Three series of NPs were employed in the XAFS study to address the effect of nano-size, metal-core and capping molecules on the structure and properties of the NPs. They are (1) thiol-capped Au NPs from 1.6nm to 4.0nm, (2) thiol-capped Au and Pd NPs of ∼2nm and (3) Au NPs of ∼4nm capped by thiol and tetraoctylammonium bromide (TOAB). The results on their local structure, bonding and d-charge distribution are presented.

Understanding Au∼98Ag∼46(SR)60 nanoclusters through investigation of their electronic and local structure by X-ray absorption fine structure

RSC Advances ◽  
2016 ◽  
Vol 6 (30) ◽  
pp. 25368-25374 ◽  
Author(s):  
Jing Liu ◽  
Katla Sai Krishna ◽  
Chanaka Kumara ◽  
Soma Chattopadhyay ◽  
Tomohiro Shibata ◽  
...  
Keyword(s):  
Fine Structure ◽  
Synchrotron Radiation ◽  
Local Structure ◽  
Metal Core ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

Synchrotron radiation-based X-ray absorption fine structure (XAFS) of thiol-stabilized Au∼98Ag∼46(SR)60 nanoclusters suggests that Au atoms preferred to occupy the metal core sites while the Ag atoms were mainly on the surface.

scholarly journals Local Structure and Dynamics of Functional Materials Studied by X-ray Absorption Fine Structure

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1315
Author(s):  
Takafumi Miyanaga
Keyword(s):  
Fine Structure ◽  
Local Structure ◽  
Chemical Reactivity ◽  
Functional Materials ◽  
X Ray ◽  
Structure And Dynamics ◽  
Absorption Fine ◽  
Structure Phase Transition ◽  
Local Electronic Structure ◽  
X Ray Absorption

X-ray absorption fine structure (XAFS) is a powerful technique used to analyze a local electronic structure, local atomic structure, and structural dynamics. In this review, I present examples of XAFS that apply to the local structure and dynamics of functional materials: (1) structure phase transition in perovskite PbTiO3 and magnetic FeRhPd alloys; (2) nano-scaled fluctuations related to their magnetic properties in Ni–Mn alloys and Fe/Cr thin films; and (3) the Debye–Waller factors related to the chemical reactivity for catalysis in polyanions and ligand exchange reaction. This study shows that the local structure and dynamics are related to the characteristic function of the materials.

Extended X-ray Absorption Fine Structure Studies of GaN Epilayers Doped in situ with Er and Eu During Molecular Beam Epitaxy

2003 ◽  
Vol 798 ◽  
Author(s):  
V. Katchkanov ◽  
J. F. W. Mosselmans ◽  
S. Dalmasso ◽  
K. P. O'Donnell ◽  
R. W. Martin ◽  
...  
Keyword(s):  
Fine Structure ◽  
Rare Earth ◽  
Molecular Beam Epitaxy ◽  
Local Structure ◽  
Molecular Beam ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
The Eu

ABSTRACTThe local structure around Er and Eu atoms introduced into GaN epilayers was studied by means of Extended X-ray Absorption Fine Structure above the appropriate rare-earth X-ray absorption edge. The samples were doped in situ during growth by Molecular Beam Epitaxy. The formation of ErN clusters was found in samples with high average Er concentrations of 32±6% and 12.4±0.8%, estimated by Wavelength Dispersive X-ray analysis. When the average Er concentration is decreased to 6.0±0.2%, 1.6±0.2% and 0.17±0.02%, Er is found in localised clusters of ErGaN phase with high local Er content. Similar behaviour is observed for Eu-doped samples. For an average Eu concentration of 30.5±0.5% clusters of pure EuN occur. Decreasing the Eu concentration to 10.4±0.5% leads to EuGaN clusters with high local Eu content. However, for a sample with an Eu concentration of 14.2±0.5% clustering of Eu was not observed.

scholarly journals Near edge x-ray absorption fine structure studies of local structure of dihexyldisulfide multilayer

2005 ◽  
Vol 54 (12) ◽  
pp. 5837
Author(s):  
Wu Tai-Quan ◽  
Tang Jing-Chang ◽  
Zhu Ping ◽  
Li Hai-Yang
Keyword(s):  
Fine Structure ◽  
Local Structure ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

XAFS Study of Molten ZrCl4 in LiCl-KCl Eutectic

2002 ◽  
Vol 57 (5) ◽  
pp. 277-280 ◽  
Author(s):  
Yoshihiro Okamoto ◽  
Haruhiko Motohashi
Keyword(s):  
Fine Structure ◽  
Coordination Number ◽  
Curve Fitting ◽  
Absorption Edge ◽  
Local Structure ◽  
Molten Mixture ◽  
X Ray ◽  
Absorption Fine ◽  
Curve Fitting Analysis ◽  
X Ray Absorption

The local structure of motlen ZrCl4 in LiCl-KCl eutectic was investigated by using an X-ray absorption fine structure (XAFS) of the Zr K-absorption edge. The nearest Zr4+-Cl- distance and coordination number from the curve fitting analysis were (2.51±0.02) Å and 5.9±0.6, respectively. These suggest that a 6-fold coordination (ZrCl6)2- is predominant in the molten mixture.

scholarly journals Solving local structure around dopants in metal nanoparticles with ab initio modeling of X-ray absorption near edge structure

2016 ◽  
Vol 18 (29) ◽  
pp. 19621-19630 ◽  
Author(s):  
Janis Timoshenko ◽  
Atal Shivhare ◽  
Robert W. J. Scott ◽  
Deyu Lu ◽  
Anatoly I. Frenkel
Keyword(s):  
Ab Initio ◽  
Metal Nanoparticles ◽  
Local Structure ◽  
Heterogeneous Catalysts ◽  
Edge Structure ◽  
X Ray ◽  
Metal Impurities ◽  
Local Environments ◽  
X Ray Absorption ◽  
Xanes Analysis

XANES analysis guided by ab initio modeling is proposed for refinement of local environments around metal impurities in heterogeneous catalysts.

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