The atomic scale structure of graphene powder studied by neutron and X-ray diffraction

2015 ◽  
Vol 48 (5) ◽  
pp. 1429-1436 ◽  
Author(s):  
Natalia Woznica ◽  
Lukasz Hawelek ◽  
Henry E. Fischer ◽  
Ivan Bobrinetskiy ◽  
Andrzej Burian
Keyword(s):  
Amorphous Materials ◽  
Structural Information ◽  
Topological Defects ◽  
Md Simulations ◽  
Atomic Scale ◽  
Wide Angle ◽  
X Rays ◽  
X Ray ◽  
Neutron Diffractometer ◽  
Bond Order Potential

The structure of graphene obtained by chemical exfoliation of graphiteviathe oxidation/reduction procedure has been determined using wide-angle scattering of neutrons and X-rays combined with computer simulations based on classical molecular dynamics (MD). A comparison of results obtained from wide-angle neutron scattering (WANS) with the D4 neutron diffractometer dedicated for liquids and amorphous materials (Institute Laue–Langevin in Grenoble) and from wide-angle X-ray scattering (WAXS) with the laboratory Rigaku-Denki D/MAX RAPID II diffractometer has shown that both techniques provide data of a good quality that can be used to derive precise and valuable structural information about graphene. To obtain detailed structural information, the paracrystal formalism has been used along with MD simulations. The MD simulations were performed at 300 K with second-generation reactive empirical bond order potential for atoms lying in the same layer and the Lennard–Jones potential for interlayer interactions. The proposed models consist of three-layered systems, 36 Å in diameter, in which mono-vacancy, di-vacancy and Stone–Thrower–Wales types of defects are introduced. The reported results show that the WANS and WAXS methods together with the MD simulations contribute to a detailed description of the graphene materials, including the presence of topological defects, which is important as their structure at the atomic scale dramatically affects their electrical and mechanical properties.

2D real space visualization of d values in polycrystalline bulk materials of different hardness

2021 ◽  
Vol 54 (2) ◽  
pp. 597-603
Author(s):  
Mari Mizusawa ◽  
Kenji Sakurai
Keyword(s):  
Lattice Distortion ◽  
Structural Information ◽  
Hardness Test ◽  
Real Space ◽  
Polycrystalline Materials ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Imaging ◽  
D Values

Conventional X-ray diffraction measurements provide some average structural information, mainly on the crystal structure of the whole area of the given specimen, which might not be very uniform and may include different crystal structures, such as co-existing crystal phases and/or lattice distortion. The way in which the lattice plane changes due to strain also might depend on the position in the sample, and the average information might have some limits. Therefore, it is important to analyse the sample with good lateral spatial resolution in real space. Although various techniques for diffraction topography have been developed for single crystals, it has not always been easy to image polycrystalline materials. Since the late 1990s, imaging technology for fluorescent X-rays and X-ray absorption fine structure has been developed via a method that does not scan either a sample or an X-ray beam. X-ray diffraction imaging can be performed when this technique is applied to a synchrotron radiation beamline with a variable wavelength. The present paper reports the application of X-ray diffraction imaging to bulk steel materials with varying hardness. In this study, the distribution of lattice distortion of hardness test blocks with different hardness was examined. Via this 2D visualization method, the grains of the crystals with low hardness are large enough to be observed by X-ray diffraction contrast in real space. The change of the d value in the vicinity of the Vickers mark has also been quantitatively evaluated.

scholarly journals Molecular Dynamics Modellization and Simulation of Water Diffusion through Plant Cutin

1999 ◽  
Vol 54 (11) ◽  
pp. 896-902 ◽  
Author(s):  
Antonio Matas ◽  
Antonio Heredia
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Structural Information ◽  
Md Simulations ◽  
Water Molecules ◽  
Plant Cuticle ◽  
X Ray Diffraction ◽  
Cross Link ◽  
X Ray ◽  
Good Agreement

Abstract A theoretical molecular modelling study has been conducted for cutin, the biopolyester that forms the main structural component of the plant cuticle. Molecular dynamics (MD) simulations, extended over several ten picoseconds, suggests that cutin is a moderately flexible netting with motional constraints mainly located at the cross-link sites of functional ester groups. This study also gives structural information essentially in accordance with previously reported experimental data, obtained from X -ray diffraction and nuclear magnetic resonance experiments. MD calculations were also performed to simulate the diffusion of water mole­cules through the cutin biopolymer. The theoretical analysis gives evidence that water perme­ation proceedes by a “hopping mechanism”. Coefficients for the diffusion of the water molecules in cutin were obtained from their mean-square displacements yielding values in good agreement with experimental data.

scholarly journals Diffraction/Scattering Tomography on multi-phase crystalline/amorphous materials

2014 ◽  
Vol 70 (a1) ◽  
pp. C139-C139 ◽  
Author(s):  
Michelle Alvarez-Murga ◽  
Pierre Bleuet ◽  
Christophe Lepoittevin ◽  
Nathalie Boudet ◽  
Gaston Gabarino ◽  
...  
Keyword(s):  
Amorphous Materials ◽  
Structural Information ◽  
Local Variation ◽  
X Rays ◽  
Complex Materials ◽  
Diffraction Scattering ◽  
Invasive Approach ◽  
Non Invasive ◽  
Phase Selectivity ◽  
Multi Phase

By suitably combining diffraction/scattering and tomography (DSCT), it is possible to access to selective submicron 2D/3D structural and micro-structural information, which cannot be obtained from separate, independent diffraction and tomography experiments. DSCT is used to discriminate between multi-phase crystalline and amorphous materials, especially when the similarities in densities limit the use of other methods. In addition, this method is sensitive to local variation of the crystalline state, texture, grain size or strains inside the object and can allow simultaneous 3D mappings of such properties. The DSCT phase-selectivity can be easily combined with fluorescence and absorption for added chemical and density resolution allowing multi-modal analyses. As samples can be used in their original state, this method can be applied without cutting or polishing them. Moreover the setup can be adapted with specific sample environments in order to monitor phase and microstructure evolution as a function of an externally controlled parameter with a non-invasive approach. After a first report on in 1998 [1], since 2008 capabilities of DSCT have been demonstrated using x-rays on complex materials as diverse as biological tissue, pigments, Portland cements, Carbon-based materials, Uranium-based nuclear fuel, Ni/Al2O3 catalysts or amorphous systems [2]. More recently, the technique has evolved towards quantitative characterization of the microstructure and stress/strain through either Rietveld or Peak Profile analyses and also pair distribution function techniques (PDF) and their application to nanostructured materials [3]. In this poster contribution, we briefly review the principle and methodology of pencil-beam based x-ray DSCT which is two-fold: (i) selective structural imaging and (ii) extraction of selective scattered patterns of ultra-minor phases.

scholarly journals Multiple application X-ray imaging chamber for single-shot diffraction experiments with femtosecond X-ray laser pulses

2014 ◽  
Vol 47 (1) ◽  
pp. 188-197 ◽  
Author(s):  
Changyong Song ◽  
Kensuke Tono ◽  
Jaehyun Park ◽  
Tomio Ebisu ◽  
Sunam Kim ◽  
...  
Keyword(s):  
Free Electron ◽  
Single Pulse ◽  
Laser Pulses ◽  
Atomic Scale ◽  
Single Shot ◽  
X Rays ◽  
Structural Investigations ◽  
X Ray ◽  
Multiple Application ◽  
X Ray Imaging

X-ray free-electron lasers (XFELs) provide intense (∼1012 photons per pulse) coherent X-rays with ultra-short (∼10−14 s) pulse lengths. X-rays of such an unprecedented nature have introduced new means of atomic scale structural investigations, and discoveries are still ongoing. Effective use of XFELs would be further accelerated on a highly adaptable platform where most of the new experiments can be realized. Introduced here is the multiple-application X-ray imaging chamber (MAXIC), which is able to carry out various single-pulse diffraction experiments including single-shot imaging, nanocrystallographic data acquisition and ultra-fast pump–probe scattering for specimens in solid, liquid and gas phases. The MAXIC established at the SPring-8 ångström compact free-electron laser (SACLA) has demonstrated successful applications in the aforementioned experiments, but is not limited to them. Also introduced are recent experiments on single-shot diffraction imaging of Au nanoparticles and serial crystallographic data collection of lysozyme crystals at SACLA.

Studies of local and intermediate range structure in crystalline and amorphous materials at high pressure using high-energy X-rays

2007 ◽  
Vol 22 (2) ◽  
pp. 108-112 ◽  
Author(s):  
Lars Ehm ◽  
Sytle M. Antao ◽  
Jiuhua Chen ◽  
Darren R. Locke ◽  
F. Marc Michel ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Atomic Structure ◽  
Amorphous Materials ◽  
High Energy ◽  
Liquid Gallium ◽  
X Rays ◽  
X Ray ◽  
X Ray Scattering ◽  
Current State

The method of high-energy total elastic X-ray scattering to determine the atomic structure of nanocrystalline, highly disordered, and amorphous materials is presented. The current state of the technique, its potential, and limitations are discussed with two successful studies on the pressure induced phase transition in mackinawite (FeS) and the high-pressure behavior of liquid gallium.

Ras Structure, Dynamics and Conformational States Assessed by MD Simulations and Solution Wide angle X‐ray Scattering

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Alicia Yvette Volmar ◽  
Hugo Guterres ◽  
Hao Zhou ◽  
Carla Mattos ◽  
Lee Makowski
Keyword(s):  
Md Simulations ◽  
Wide Angle ◽  
Conformational States ◽  
X Ray ◽  
Structure Dynamics ◽  
X Ray Scattering ◽  
Ray Scattering

Depth-Resolved Characterization of Perylenediimide Side-Chain Polymer Thin Film Structure Using Grazing-Incidence Wide-Angle X-ray Diffraction with Tender X-rays

Langmuir ◽  
2018 ◽  
Vol 34 (29) ◽  
pp. 8516-8521 ◽  
Author(s):  
Kazutaka Kamitani ◽  
Ayumi Hamada ◽  
Kazutoshi Yokomachi ◽  
Kakeru Ninomiya ◽  
Kiyu Uno ◽  
...  
Keyword(s):  
Grazing Incidence ◽  
Film Structure ◽  
Side Chain ◽  
Wide Angle ◽  
X Rays ◽  
X Ray Diffraction ◽  
Polymer Thin Film ◽  
Chain Polymer ◽  
X Ray

scholarly journals Application of maximum-entropy electrostatic potential in Materials Science.

2014 ◽  
Vol 70 (a1) ◽  
pp. C101-C101
Author(s):  
Eiji Nishibori
Keyword(s):  
Maximum Entropy ◽  
Electrostatic Potential ◽  
Diffraction Data ◽  
Materials Science ◽  
Structural Information ◽  
Entropy Method ◽  
Atomic Scale ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Sites

Charge density (CD) studies by Maximum Entropy Method (MEM) (Sakata & Sato, 1990) from x-ray diffraction data have been widely applied to solve problems and questions in materials science during past two decades. Encapsulations of metal atoms (Takata et al, 1995), gas molecules, as well as protein molecules in the materials have been visualized as MEM CDs. The MEM CD technique is now regarded as a sophisticated technique for visualization in atomic scale. Electrostatic potential (EP) and electric field (EF) from x-ray diffraction data using MEM have been developed in 2006 (Tanaka et al, 2006). The EP & EF successfully applied to ferroelectric material PbTiO3 and a charge ordered manganite system. The method has huge potential in materials science since interaction in the non-atomic region can be visualized experimentally. One of the promising target for EP & EF analysis is host-guest systems, such as porous coordination polymers (PCPs), zeolites, clathrates as well as endohedral metallofullerenes[3]. In the case of host-guest systems, the guest atom(s) or molecule(s) are located in spatially wider sites in comparison to other type of materials. Therefore the detailed structural information in the spatially wider sites is one of the most important issues. In the present study, I present an application of MEM EP & EF analysis to host-guest related system, icosahedral B12 cluster materials and hydrogen adsorbed PCP. The EP studies clearly visualize doping sites in B12 based superconductor and adsorption sites in PCP. The EF enables us to estimate quantitative interaction from host to guest. The quantitative evaluation really bridges between experiment and theory in materials science.

X-Ray Scattering Studies of Thin Films and Multilayers

1989 ◽  
Vol 151 ◽  
Author(s):  
G. S. Cargill
Keyword(s):  
Thin Films ◽  
Energy Spectrum ◽  
Synchrotron Radiation ◽  
Ultrathin Films ◽  
Amorphous Materials ◽  
Atomic Scale ◽  
X Ray ◽  
X Ray Scattering ◽  
Broad Energy ◽  
Ray Scattering

ABSTRACTX-ray scattering experiments provide important information about the atomic scale structure and the microstructure of thin films and multilayers. The high intensity, brightness, and broad energy spectrum of synchrotron radiation greatly extend capabilities of scattering experiments, particularly for scattering from ultrathin films and for anomalous dispersion scattering from alloys. Examples of scattering studies of both crystalline and amorphous materials are given in this overview.

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