scholarly journals A previously unknown cyclic alkanolamine and molecular ranking using the pair distribution function

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Gianpiero Gallo ◽  
Maxwell W. Terban ◽  
Igor Moudrakovski ◽  
Tatjana Huber ◽  
Martin Etter ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Distribution Function ◽  
Pair Distribution Function ◽  
Real Space ◽  
Gaseous Ammonia ◽  
Orthorhombic Space Group ◽  
Hexagonal Ring ◽  
Cell Parameters ◽  
Carbon And Nitrogen ◽  
Pdf Analysis

A new six-membered cyclic alkanolamine with chemical formula C6H15N3O3 was synthesized by the reaction of glycolaldehyde with gaseous ammonia. The molecular structure, characterized by a hexagonal ring of alternating carbon and nitrogen atoms with three hydroxymethyl groups attached to the carbon atoms, could not be unambiguously determined by elemental analysis and 1H/13C/15N NMR. The molecular structure and conformation were further determined using a combination of vibrational spectroscopy (IR and Raman) and real-space pair distribution function (PDF) analysis. The crystal structure was determined ab initio from laboratory X-ray powder diffraction (XRPD) with orthorhombic space group Ama2 (No. 40) and unit-cell parameters a = 12.1054 (2) Å, b = 13.5537 (2) Å and c = 5.20741 (8) Å. Consistent structure models could be obtained by symmetry-independent PDF and PDF-Rietveld co-refinements. Independent local structure refinements indicate that the most likely deviations from the average structure consist of small tilting and translational distortions of hydrogen-bonded molecular stacks. Thermal analysis (TG/DTA) and temperature-dependent XRPD measurements were also performed to determine the thermal behavior.

scholarly journals Precise implications for real-space pair distribution function modeling of effects intrinsic to modern time-of-flight neutron diffractometers

2018 ◽  
Vol 74 (4) ◽  
pp. 293-307 ◽  
Author(s):  
Daniel Olds ◽  
Claire N. Saunders ◽  
Megan Peters ◽  
Thomas Proffen ◽  
Joerg Neuefeind ◽  
...  
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Amorphous Materials ◽  
Best Practice ◽  
Time Of Flight ◽  
Real Space ◽  
Mitigation Strategies ◽  
Total Scattering ◽  
Conventional Analysis ◽  
Pdf Analysis

Total scattering and pair distribution function (PDF) methods allow for detailed study of local atomic order and disorder, including materials for which Rietveld refinements are not traditionally possible (amorphous materials, liquids, glasses and nanoparticles). With the advent of modern neutron time-of-flight (TOF) instrumentation, total scattering studies are capable of producing PDFs with ranges upwards of 100–200 Å, covering the correlation length scales of interest for many materials under study. Despite this, the refinement and subsequent analysis of data are often limited by confounding factors that are not rigorously accounted for in conventional analysis programs. While many of these artifacts are known and recognized by experts in the field, their effects and any associated mitigation strategies largely exist as passed-down `tribal' knowledge in the community, and have not been concisely demonstrated and compared in a unified presentation. This article aims to explicitly demonstrate, through reviews of previous literature, simulated analysis and real-world case studies, the effects of resolution, binning, bounds, peak shape, peak asymmetry, inconsistent conversion of TOF to d spacing and merging of multiple banks in neutron TOF data as they directly relate to real-space PDF analysis. Suggestions for best practice in analysis of data from modern neutron TOF total scattering instruments when using conventional analysis programs are made, as well as recommendations for improved analysis methods and future instrument design.

scholarly journals A simple correction for the parallax effect in X-ray pair distribution function measurements

2019 ◽  
Vol 52 (5) ◽  
pp. 1072-1076 ◽  
Author(s):  
Frederick Marlton ◽  
Oleh Ivashko ◽  
Martin v. Zimmerman ◽  
Olof Gutowski ◽  
Ann-Christin Dippel ◽  
...  
Keyword(s):  
Distribution Function ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Pair Distribution Function ◽  
Reference Data ◽  
Real Space ◽  
X Ray ◽  
Local Structures ◽  
Pdf Analysis ◽  
Complex Nanostructures

Total scattering and pair distribution function (PDF) analysis has created new insights that traditional powder diffraction methods have been unable to achieve in understanding the local structures of materials exhibiting disorder or complex nanostructures. Care must be taken in such analyses as subtle and discrete features in the PDF can easily be artefacts generated in the measurement process, which can result in unphysical models and interpretation. The focus of this study is an artefact called the parallax effect, which can occur in area detectors with thick detection layers during the collection of X-ray PDF data. This effect results in high-Q peak offsets, which subsequently cause an r-dependent shift in the PDF peak positions in real space. Such effects should be accounted for if a truly accurate model is to be achieved, and a simple correction that can be conducted via a Rietveld refinement against the reference data is proposed.

Structural Analysis of Al, Ni, and Cu Using the Maximum Entropy Method, Multipole and Pair Distribution Function

2009 ◽  
Vol 64 (5-6) ◽  
pp. 361-369 ◽  
Author(s):  
Muthaian Charles Robert ◽  
Ramachandran Saravanan ◽  
Krishnamoorthy Saravanakumar ◽  
Murugesan Prema Rani
Keyword(s):  
Distribution Function ◽  
Maximum Entropy ◽  
Electron Density ◽  
Pair Distribution Function ◽  
Maximum Entropy Method ◽  
Entropy Method ◽  
Cell Parameters ◽  
Pdf Analysis ◽  
Spherical Core ◽  
Electron Density Profiles

The average and local structures of the metals Al, Ni, and Cu have been elucidated for the first time using the MEM (maximum entropy method), multipole and PDF (pair distribution function). The bonding between the constituent atoms in all these systems is found to be well pronounced and clearly seen from the electron density maps. The MEM maps of all three systems show the spherical core nature of the atoms. The mid bond electron density profiles of Al, Ni, and Cu reveal the metallic nature of the bonding. The local structure using the PDF profile of Ni is compared with that of previously reported results. The R value in the present work using low Q XRD data for the PDF analysis of Ni is close to the value in the literature using high Q synchrotron data. The cell parameters and displacement parameters are also studied and compared with the reported values.

Real-Space X-Ray Pair Distribution Function Analysis and Molecular-Dynamics Modelling of Diflunisal Channel Hydrates

2020 ◽  
Author(s):  
Anuradha Pallipurath ◽  
Francesco Civati ◽  
Jonathan Skelton ◽  
Dean Keeble ◽  
Clare Crowley ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Structural Dynamics ◽  
First Principles ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Real Space ◽  
X Ray ◽  
Dynamics Modelling ◽  
Dynamics Simulations

X-ray pair distribution function analysis is used with first-principles molecular dynamics simulations to study the co-operative H<sub>2</sub>O binding, structural dynamics and host-guest interactions in the channel hydrate of diflunisal.

scholarly journals There's no place like real-space: elucidating size-dependent atomic structure of nanomaterials using pair distribution function analysis

2020 ◽  
Vol 2 (6) ◽  
pp. 2234-2254 ◽  
Author(s):  
Troels Lindahl Christiansen ◽  
Susan R. Cooper ◽  
Kirsten M. Ø. Jensen
Keyword(s):  
Distribution Function ◽  
Atomic Structure ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Real Space ◽  
Size Dependent ◽  
Structure Of Nanomaterials

We review the use of pair distribution function analysis for characterization of atomic structure in nanomaterials.

scholarly journals Improved Models for Metallic Nanoparticle Cores from Atomic Pair Distribution Function (PDF) Analysis

2018 ◽  
Vol 122 (51) ◽  
pp. 29498-29506 ◽  
Author(s):  
Soham Banerjee ◽  
Chia-Hao Liu ◽  
Jennifer D. Lee ◽  
Anton Kovyakh ◽  
Viktoria Grasmik ◽  
...  
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Metallic Nanoparticle ◽  
Atomic Pair Distribution Function ◽  
Atomic Pair ◽  
Pdf Analysis

scholarly journals Structural Analysis of Ligand Protected Smaller Metallic Nanocrystals by Atomic Pair Distribution Function Under Precession Electron Diffraction

2019 ◽  
Author(s):  
M. Mozammel Hoque ◽  
Sandra Vergara ◽  
Partha P. Das ◽  
Daniel Ugarte ◽  
Ulises Santiago ◽  
...  
Keyword(s):  
Distribution Function ◽  
Electron Diffraction ◽  
Pair Distribution Function ◽  
Electron Diffraction Data ◽  
Face Centered Cubic ◽  
X Ray ◽  
Atomic Pair Distribution Function ◽  
Atomic Pair ◽  
Pdf Analysis ◽  
Precession Electron Diffraction

Atomic pair distribution function (PDF) analysis has been widely used to investigate nanocrystalline and structurally disordered materials. Experimental PDFs retrieved from electron diffraction (ePDF) in transmission electron microscopy (TEM) represent an attractive alternative to traditional PDF obtained from synchrotron X-ray sources, when employed on minute samples. Nonetheless, the inelastic scattering produced by the large dynamical effects of electron diffraction may obscure the interpretation of ePDF. In the present work, precession electron diffraction (PED-TEM) has been employed to obtain the ePDF of two different sub-monolayer samples ––lipoic acid protected (~ 4.5 nm) and hexanethiolated(~ 4.2 nm, ~ 400-kDa core mass) gold nanoparticles­­––randomly oriented and measured at both liquid-nitrogen and room temperatures, with high dynamic-range detection of a CMOS camera. The electron diffraction data were processed to obtain ePDFs which were subsequently compared with PDF of different ideal structure-models. The results demonstrate that the PED-ePDF data is sensitive to different crystalline structures such as monocrystalline (truncated octahedra) versus multiply-twinned (decahedra, icosahedra) structuresof the face-centered cubic gold lattice. The results indicate that PED reduces the residual from 46% to 29%; in addition, the combination of PED and low temperature further reduced the residual to 23%, which is comparable to X-ray PDF analysis. Furthermore, the inclusion of PED resulted in a better estimation of the coordination number from ePDF. To the best of our knowledge, the precessed electron-beam technique (PED) has not been previously applied to nanoparticles for analysis by the ePDF method.

scholarly journals SASPDF: pair distribution function analysis of nanoparticle assemblies from small-angle scattering data

2020 ◽  
Vol 53 (3) ◽  
pp. 699-709 ◽  
Author(s):  
Chia-Hao Liu ◽  
Eric M. Janke ◽  
Ruipen Li ◽  
Pavol Juhás ◽  
Oleg Gang ◽  
...  
Keyword(s):  
Distribution Function ◽  
Small Angle ◽  
Pair Distribution Function ◽  
Function Analysis ◽  
Small Angle Scattering ◽  
Scattering Data ◽  
Nanoparticle Assemblies ◽  
Angle Scattering ◽  
Pdf Analysis ◽  
Crystallite Sizes

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.

scholarly journals Rapid-acquisition pair distribution function (RA-PDF) analysis

2003 ◽  
Vol 36 (6) ◽  
pp. 1342-1347 ◽  
Author(s):  
Peter J. Chupas ◽  
Xiangyun Qiu ◽  
Jonathan C. Hanson ◽  
Peter L. Lee ◽  
Clare P. Grey ◽  
...  
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
High Energy ◽  
Data Sets ◽  
Crystalline Materials ◽  
Rapid Acquisition ◽  
Atomic Pair Distribution Function ◽  
Pdf Analysis ◽  
Diffraction Patterns ◽  
Counting Statistics

An image-plate (IP) detector coupled with high-energy synchrotron radiation was used for atomic pair distribution function (PDF) analysis, with high probed momentum transferQmax≤ 28.5 Å−1, from crystalline materials. Materials with different structural complexities were measured to test the validity of the quantitative data analysis. Experimental results are presented for crystalline Ni, crystalline α-AlF3, and the layered Aurivillius type oxides α-Bi4V2O11and γ-Bi4V1.7Ti0.3O10.85. Overall, the diffraction patterns show good counting statistics, with measuring time from one to tens of seconds. The PDFs obtained are of high quality. Structures may be refined from these PDFs, and the structural models are consistent with the published literature. Data sets from similar samples are highly reproducible.

X-ray and neutron total scattering analysis of Hy·(Bi0.2Ca0.55Sr0.25)(Ag0.25Na0.75)Nb3O10·xH2O perovskite nanosheet booklets with stacking disorder

2016 ◽  
Vol 31 (2) ◽  
pp. 126-134 ◽  
Author(s):  
Peter Metz ◽  
Robert Koch ◽  
Bernadette Cladek ◽  
Katharine Page ◽  
Joerg Neuefeind ◽  
...  
Keyword(s):  
Pair Distribution Function ◽  
Real Space ◽  
Standard Normal Distribution ◽  
Recursive Method ◽  
Perovskite Layer ◽  
X Ray ◽  
X Ray Scattering ◽  
Pdf Analysis ◽  
Standard Normal ◽  
Stacking Disorder

Ion-exchanged Aurivillius materials form perovskite nanosheet booklets wherein well-defined bi-periodic sheets, with ~11.5 Å thickness, exhibit extensive stacking disorder. The perovskite layer contents were defined initially using combined synchrotron X-ray and neutron Rietveld refinement of the parent Aurivillius structure. The structure of the subsequently ion-exchanged material, which is disordered in its stacking sequence, is analyzed using both pair distribution function (PDF) analysis and recursive method simulations of the scattered intensity. Combined X-ray and neutron PDF refinement of supercell stacking models demonstrates sensitivity of the PDF to both perpendicular and transverse stacking vector components. Further, hierarchical ensembles of stacking models weighted by a standard normal distribution are demonstrated to improve PDF fit over 1–25 Å. Recursive method simulations of the X-ray scattering profile demonstrate agreement between the real space stacking analysis and more conventional reciprocal space methods. The local structure of the perovskite sheet is demonstrated to relax only slightly from the Aurivillius structure after ion exchange.

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