The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Simon J L Billinge - One of the best experts on this subject based on the ideXlab platform.
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a cloud platform for atomic Pair Distribution Function analysis pdfitc
Acta Crystallographica Section A, 2021Co-Authors: Long Yang, Simon J L Billinge, Elizabeth Culbertson, Nancy K Thomas, Hung T Vuong, Emil T S Kjaer, Kirsten M O Jensen, Matthew G TuckerAbstract:A cloud web platform for analysis and interpretation of atomic Pair Distribution Function (PDF) data (PDFitc) is described. The platform is able to host applications for PDF analysis to help researchers study the local and nanoscale structure of nanostructured materials. The applications are designed to be powerful and easy to use and can, and will, be extended over time through community adoption and development. The currently available PDF analysis applications, structureMining, spacegroupMining and similarityMapping, are described. In the first and second the user uploads a single PDF and the application returns a list of best-fit candidate structures, and the most likely space group of the underlying structure, respectively. In the third, the user can upload a set of measured or calculated PDFs and the application returns a matrix of Pearson correlations, allowing assessment of the similarity between different data sets. structureMining is presented here as an example to show the easy-to-use workflow on PDFitc. In the future, as well as using the PDFitc applications for data analysis, it is hoped that the community will contribute their own codes and software to the platform.
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saspdf Pair Distribution Function analysis of nanoparticle assemblies from small angle scattering data
Journal of Applied Crystallography, 2020Co-Authors: Chiahao Liu, Eric M Janke, Pavol Juhas, Oleg Gang, Dmitri V Talapin, Simon J L BillingeAbstract:sasPDF, a method for characterizing the structure of nanoparticle assemblies (NPAs), is presented. The method is an extension of the atomic Pair Distribution Function (PDF) analysis to the small-angle scattering (SAS) regime. The PDFgetS3 software package for computing the PDF from SAS data is also presented. An application of the sasPDF method to characterize structures of representative NPA samples with different levels of structural order is then demonstrated. The sasPDF method quantitatively yields information such as structure, disorder and crystallite sizes of ordered NPA samples. The method was also used to successfully model the data from a disordered NPA sample. The sasPDF method offers the possibility of more quantitative characterizations of NPA structures for a wide class of samples.
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saspdf Pair Distribution Function analysis of nanoparticle assemblies from small angle scattering data
arXiv: Materials Science, 2019Co-Authors: Chiahao Liu, Eric M Janke, Pavol Juhas, Oleg Gang, Dmitri V Talapin, Simon J L BillingeAbstract:We extends Pair Distribution Function (PDF) analysis into the small-angle scattering (SAS) regime and describe the data collection protocol for optimum data quality. We also present the PDFgetS3 software package that can be readily used to extract the PDF from small-angle scattering data. We then apply the sasPDF method to investigate structures of some representative nanoparticle assemblies (NPA) samples with different levels of structural order.
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The rise of the X-ray atomic Pair Distribution Function method: a series of fortunate events.
Philosophical transactions. Series A Mathematical physical and engineering sciences, 2019Co-Authors: Simon J L BillingeAbstract:The atomic Pair Distribution Function (PDF) technique is a powerful approach to gain quantitative insight into the structure of materials where the structural coherence extends only over a few nano...
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total scattering Pair Distribution Function of organic material from powder electron diffraction data
Microscopy and Microanalysis, 2015Co-Authors: Tatiana Gorelik, Martin U Schmidt, Ute Kolb, Simon J L BillingeAbstract:This paper shows that Pair-Distribution Function (PDF) analyses can be carried out on organic and organometallic compounds from powder electron diffraction data. Different experimental setups are demonstrated, including selected area electron diffraction and nanodiffraction in transmission electron microscopy or nanodiffraction in scanning transmission electron microscopy modes. The methods were demonstrated on organometallic complexes (chlorinated and unchlorinated copper phthalocyanine) and on purely organic compounds (quinacridone). The PDF curves from powder electron diffraction data, called ePDF, are in good agreement with PDF curves determined from X-ray powder data demonstrating that the problems of obtaining kinematical scattering data and avoiding beam damage of the sample are possible to resolve.
Thomas Proffen - One of the best experts on this subject based on the ideXlab platform.
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local atomic ordering in batao2n studied by neutron Pair Distribution Function analysis and density Functional theory
Chemistry of Materials, 2007Co-Authors: Katharine Page, Thomas Proffen, Matthew W Stoltzfus, Youngil Kim, Patrick M Woodward, Anthony Cheetham K And, Ram SeshadriAbstract:The local structure and oxygen/nitrogen ordering of the high permittivity perovskite BaTaO2N has been studied using a combination of neutron total scattering and density Functional electronic structure calculations. Although the average structure as revealed by neutron diffraction Rietveld analysis is cubic Pm3m with no evidence of O/N ordering, the local structure as revealed by Pair Distribution Function analysis of the total neutron scattering appears to favor a cis configuration of the TaO4N2 polyhedra with small Ta displacements toward the N atoms. Density Functional calculations similarly suggest that the cis TaO4N2 polyhedron is more stable than the corresponding trans variant.
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Pair Distribution Function and structure factor of spherical particles
Physical Review B, 2006Co-Authors: Rafael C Howell, Thomas Proffen, S D ConradsonAbstract:The availability of neutron spallation-source instruments that provide total scattering powder diffraction has led to an increased application of real-space structure analysis using the Pair Distribution Function. Currently, the analytical treatment of finite size effects within Pair Distribution refinement procedures is limited. To that end, an envelope Function is derived which transforms the Pair Distribution Function of an infinite solid into that of a spherical particle with the same crystal structure. Distributions of particle sizes are then considered, and the associated envelope Function is used to predict the particle size Distribution of an experimental sample of gold nanoparticles from its Pair Distribution Function alone. Finally, complementing the wealth of existing diffraction analysis, the peak broadening for the structure factor of spherical particles, expressed as a convolution derived from the envelope Functions, is calculated exactly for all particle size Distributions considered, and peak maxima, offsets, and asymmetries are discussed.
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Pair Distribution Function and structure factor of spherical particles
Physical Review B, 2006Co-Authors: Rafael C Howell, Thomas Proffen, S D ConradsonAbstract:The availability of neutron spallation-source instruments that provide total scattering powder diffraction has led to an increased application of real-space structure analysis using the Pair Distribution Function. Currently, the analytical treatment of finite size effects within Pair Distribution refinement procedures is limited. To that end, an envelope Function is derived which transforms the Pair Distribution Function of an infinite solid into that of a spherical particle with the same crystal structure. Distributions of particle sizes are then considered, and the associated envelope Function is used to predict the particle size Distribution of an experimental sample of gold nanoparticles from its Pair Distribution Function alone. Finally, complementing the wealth of existing diffraction analysis, the peak broadening for the structure factor of spherical particles, expressed as a convolution derived from the envelope Functions, is calculated exactly for all particle size Distributions considered, and peak maxima, offsets, and asymmetries are discussed.Comment: 7 pages, 6 figure
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A Pair Distribution Function analysis of zeolite beta
Microporous and Mesoporous Materials, 2005Co-Authors: María M. Martínez-iñesta, Thomas Proffen, I. Peral, Raul F. LoboAbstract:We describe the structural refinement of zeolite beta using the local structure obtained with the Pair Distribution Function (PDF) method. A high quality synchrotron and two neutron scattering datasets were obtained on two samples of siliceous zeolite beta. The two polytypes that make up zeolite beta have the same local structure; therefore refinement of the two structures was possible using the same experimental PDF. Optimized structures of polytypes A and B were used to refine the structures using the program PDFfit. Refinements using only the synchrotron or the neutron datasets gave results inconsistent with each other but a cyclic refinement with the two datasets gave a good fit to both PDFs. The results show that the PDF method is a viable technique to analyze the local structure of disordered zeolites. However, given the complexity of most zeolite frameworks, the use of both X-ray and neutron radiation and high-resolution patterns is essential to obtain reliable refinements.
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reciprocal space instrumental effects on the real space neutron atomic Pair Distribution Function
Journal of Applied Crystallography, 2004Co-Authors: Xiangyun Qiu, Pavol Juhas, Thomas Proffen, E. S. Božin, Simon J L BillingeAbstract:An atomic Pair Distribution Function (PDF) neutron powder diffraction round-robin experiment was performed on six diffractometers at three spallation sources. Instrument-specific effects on the real-space PDF were investigated, such as finite measurement range, the instrument resolution and the asymmetric shape of diffraction peaks. Two illustrative samples, a perfectly long-range-ordered element, Pb, and a locally strained alloy ZnSe0.5Te0.5, were measured at low temperatures. Various aspects of the PDF were explored, either qualitatively by direct comparison or quantitatively via structural modelling. Future implementation of modelling codes incorporating some of these instrumental effects are also discussed.
Oleg Gang - One of the best experts on this subject based on the ideXlab platform.
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saspdf Pair Distribution Function analysis of nanoparticle assemblies from small angle scattering data
Journal of Applied Crystallography, 2020Co-Authors: Chiahao Liu, Eric M Janke, Pavol Juhas, Oleg Gang, Dmitri V Talapin, Simon J L BillingeAbstract:sasPDF, a method for characterizing the structure of nanoparticle assemblies (NPAs), is presented. The method is an extension of the atomic Pair Distribution Function (PDF) analysis to the small-angle scattering (SAS) regime. The PDFgetS3 software package for computing the PDF from SAS data is also presented. An application of the sasPDF method to characterize structures of representative NPA samples with different levels of structural order is then demonstrated. The sasPDF method quantitatively yields information such as structure, disorder and crystallite sizes of ordered NPA samples. The method was also used to successfully model the data from a disordered NPA sample. The sasPDF method offers the possibility of more quantitative characterizations of NPA structures for a wide class of samples.
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saspdf Pair Distribution Function analysis of nanoparticle assemblies from small angle scattering data
arXiv: Materials Science, 2019Co-Authors: Chiahao Liu, Eric M Janke, Pavol Juhas, Oleg Gang, Dmitri V Talapin, Simon J L BillingeAbstract:We extends Pair Distribution Function (PDF) analysis into the small-angle scattering (SAS) regime and describe the data collection protocol for optimum data quality. We also present the PDFgetS3 software package that can be readily used to extract the PDF from small-angle scattering data. We then apply the sasPDF method to investigate structures of some representative nanoparticle assemblies (NPA) samples with different levels of structural order.
Pavol Juhas - One of the best experts on this subject based on the ideXlab platform.
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saspdf Pair Distribution Function analysis of nanoparticle assemblies from small angle scattering data
Journal of Applied Crystallography, 2020Co-Authors: Chiahao Liu, Eric M Janke, Pavol Juhas, Oleg Gang, Dmitri V Talapin, Simon J L BillingeAbstract:sasPDF, a method for characterizing the structure of nanoparticle assemblies (NPAs), is presented. The method is an extension of the atomic Pair Distribution Function (PDF) analysis to the small-angle scattering (SAS) regime. The PDFgetS3 software package for computing the PDF from SAS data is also presented. An application of the sasPDF method to characterize structures of representative NPA samples with different levels of structural order is then demonstrated. The sasPDF method quantitatively yields information such as structure, disorder and crystallite sizes of ordered NPA samples. The method was also used to successfully model the data from a disordered NPA sample. The sasPDF method offers the possibility of more quantitative characterizations of NPA structures for a wide class of samples.
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saspdf Pair Distribution Function analysis of nanoparticle assemblies from small angle scattering data
arXiv: Materials Science, 2019Co-Authors: Chiahao Liu, Eric M Janke, Pavol Juhas, Oleg Gang, Dmitri V Talapin, Simon J L BillingeAbstract:We extends Pair Distribution Function (PDF) analysis into the small-angle scattering (SAS) regime and describe the data collection protocol for optimum data quality. We also present the PDFgetS3 software package that can be readily used to extract the PDF from small-angle scattering data. We then apply the sasPDF method to investigate structures of some representative nanoparticle assemblies (NPA) samples with different levels of structural order.
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reciprocal space instrumental effects on the real space neutron atomic Pair Distribution Function
Journal of Applied Crystallography, 2004Co-Authors: Xiangyun Qiu, Pavol Juhas, Thomas Proffen, E. S. Božin, Simon J L BillingeAbstract:An atomic Pair Distribution Function (PDF) neutron powder diffraction round-robin experiment was performed on six diffractometers at three spallation sources. Instrument-specific effects on the real-space PDF were investigated, such as finite measurement range, the instrument resolution and the asymmetric shape of diffraction peaks. Two illustrative samples, a perfectly long-range-ordered element, Pb, and a locally strained alloy ZnSe0.5Te0.5, were measured at low temperatures. Various aspects of the PDF were explored, either qualitatively by direct comparison or quantitatively via structural modelling. Future implementation of modelling codes incorporating some of these instrumental effects are also discussed.
Dominic J. Tildesley - One of the best experts on this subject based on the ideXlab platform.
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The Pair Distribution Function in the planar gas-liquid interface: Application to the calculation of the surface tension.
The Journal of chemical physics, 2019Co-Authors: Florent Goujon, Patrice Malfreyt, Dominic J. TildesleyAbstract:A Monte Carlo simulation is used to calculate the Pair Distribution Function g(2)r1,r2 for a planar gas-liquid interface. Due to the cylindrical symmetry of the system, g(2) can be stored as a three-dimensional array that can be readily manipulated and used to calculate the surface tension and the single atom density profile directly. The consistency and accuracy of our calculation of g(2)(r1, r2) is demonstrated by a calculation of the single atom density through the first Born-Green-Yvon equation. We show that the surface tension calculated directly from the Pair Distribution Function and from other well-established routes is completely consistent. In the case of the gas-liquid interface for argon modeled with an explicit inclusion of the three-body forces, an accurate Pair Distribution can be used to estimate the long-range contribution to the three-body part of the surface tension. A detailed analysis of this correction, its dependence on the three-body cutoff, and its overall contribution to the surface tension are presented.
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The Pair Distribution Function in the planar gas–liquid interface: Application to the calculation of the surface tension
Journal of Chemical Physics, 2019Co-Authors: Florent Goujon, Patrice Malfreyt, Dominic J. TildesleyAbstract:A Monte Carlo simulation is used to calculate the Pair Distribution Function g(2)(r1,r2) for a planar gas–liquid interface. Due to the cylindrical symmetry of the system, g(2) can be stored as a three-dimensional array that can be readily manipulated and used to calculate the surface tension and the single atom density profile directly. The consistency and accuracy of our calculation of g(2)(r1, r2) is demonstrated by a calculation of the single atom density through the first Born–Green–Yvon equation. We show that the surface tension calculated directly from the Pair Distribution Function and from other well–established routes is completely consistent. In the case of the gas-liquid interface for argon modeled with an explicit inclusion of the three-body forces, an accurate Pair Distribution can be used to estimate the long-range contribution to the three–body part of the surface tension. A detailed analysis of this correction, its dependence on the three–body cutoff, and its overall contribution to the surface tension are presented.
