Reliability of Orientational Order Parameters Determined from Two-dimensional X-ray Diffraction Patterns: A Simulation Study

ChemPhysChem ◽  
2016 ◽  
Vol 17 (11) ◽  
pp. 1568-1572 ◽  
Author(s):  
Frank Jenz ◽  
Stefan Jagiella ◽  
Matthew A. Glaser ◽  
Frank Giesselmann
Keyword(s):  
Simulation Study ◽  
Orientational Order ◽  
Order Parameters ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

Comparison of the orientational order parameters determined from X-ray diffraction and13C NMR studies of a hockey stick-shaped compound

2009 ◽  
Vol 82 (6) ◽  
pp. 433-443 ◽  
Author(s):  
Gautam Sarkar ◽  
Malay Kumar Das ◽  
Ranjit Paul ◽  
Banani Das ◽  
Wolfgang Weissflog
Keyword(s):  
Orientational Order ◽  
Order Parameters ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Hockey Stick ◽  
X Ray

Exfoliated single molecular layers of Mn0.8PS3 and Cd0.8PS3

2005 ◽  
Vol 20 (5) ◽  
pp. 1107-1112 ◽  
Author(s):  
R.F. Frindt ◽  
D. Yang ◽  
P. Westreich
Keyword(s):  
Ion Exchange ◽  
Structure Factor ◽  
Single Layer ◽  
Layered Compounds ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vacancy Ordering ◽  
Diffraction Patterns ◽  
Molecular Layers

The layered compounds MnPS3 and CdPS3 were exfoliated to form single molecular layers of Mn0.8PS3 and Cd0.8PS3 in suspension in water by ion exchange. The x-ray diffraction patterns of the two single-layer suspensions showed profound differences in some of the Bragg peaks, and we demonstrated that the differences are not due to the quality or size of the single layers, but are caused by structure factor modulations of the Warren tail for two-dimensional systems. We also demonstrated that the Cd or Mn vacancies generated in the exfoliation process are not ordered at long range, in contrast to an earlier report of vacancy ordering on intercalated MnPS3.

scholarly journals Removing multiple outliers and single-crystal artefacts from X-ray diffraction computed tomography data

2015 ◽  
Vol 48 (6) ◽  
pp. 1943-1955 ◽  
Author(s):  
Antonios Vamvakeros ◽  
Simon D. M. Jacques ◽  
Marco Di Michiel ◽  
Vesna Middelkoop ◽  
Christopher K. Egan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Single Crystal ◽  
Tomographic Reconstruction ◽  
Projection Data ◽  
Data Sets ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Tomography Data

This paper reports a simple but effective filtering approach to deal with single-crystal artefacts in X-ray diffraction computed tomography (XRD-CT). In XRD-CT, large crystallites can produce spots on top of the powder diffraction rings, which, after azimuthal integration and tomographic reconstruction, lead to line/streak artefacts in the tomograms. In the simple approach presented here, the polar transform is taken of collected two-dimensional diffraction patterns followed by directional median/mean filtering prior to integration. Reconstruction of one-dimensional diffraction projection data sets treated in such a way leads to a very significant improvement in reconstructed image quality for systems that exhibit powder spottiness arising from large crystallites. This approach is not computationally heavy which is an important consideration with big data sets such as is the case with XRD-CT. The method should have application to two-dimensional X-ray diffraction data in general where such spottiness arises.

CRAFS: a model to analyze two-dimensional X-ray diffraction patterns of plant cellulose

2013 ◽  
Vol 46 (4) ◽  
pp. 1196-1210 ◽  
Author(s):  
Rafael P. Oliveira ◽  
Carlos Driemeier
Keyword(s):  
Fine Structure ◽  
Higher Plants ◽  
Rietveld Method ◽  
Renewable Resource ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Broadening ◽  
Cellulose Iβ ◽  
Diffraction Patterns

Cellulose from higher plants is a vast renewable resource organized as crystals. Analysis of these crystals by X-ray diffraction poses very specific challenges, including ubiquitous crystallite texture and substantial overlapping of diffraction peaks. In this article, a tailor-made model named Cellulose Rietveld Analysis for Fine Structure (CRAFS) is developed to analyze two-dimensional X-ray diffraction patterns from raw and processed plant cellulose. One-dimensional powder diffractograms are analyzable as a particular case. The CRAFS model considers cellulose Iβ crystal structure, fibrillar crystal shape, paracrystalline peak broadening, pseudo-Voigt peak profiles, harmonic crystallite orientation distribution function and diffraction in fiber geometry. Formulated on the basis of the Rietveld method, CRAFS is presently written in the MATLAB computing language. A set of meaningful coefficients are output from each analyzed pattern. To exemplify model applicability, representative samples are analyzed, bringing some general insights and evidencing the model's potential for systematic parameterization of the fine structure of raw and processed plant celluloses.

scholarly journals Femtosecond X-ray diffraction from two-dimensional protein crystals

IUCrJ ◽  
2014 ◽  
Vol 1 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Matthias Frank ◽  
David B. Carlson ◽  
Mark S. Hunter ◽  
Garth J. Williams ◽  
Marc Messerschmidt ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bragg Diffraction ◽  
Protein Crystal ◽  
Protein Crystals ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Linac Coherent Light Source ◽  
Diffraction Patterns ◽  
Better Than

X-ray diffraction patterns from two-dimensional (2-D) protein crystals obtained using femtosecond X-ray pulses from an X-ray free-electron laser (XFEL) are presented. To date, it has not been possible to acquire transmission X-ray diffraction patterns from individual 2-D protein crystals due to radiation damage. However, the intense and ultrafast pulses generated by an XFEL permit a new method of collecting diffraction data before the sample is destroyed. Utilizing a diffract-before-destroy approach at the Linac Coherent Light Source, Bragg diffraction was acquired to better than 8.5 Å resolution for two different 2-D protein crystal samples each less than 10 nm thick and maintained at room temperature. These proof-of-principle results show promise for structural analysis of both soluble and membrane proteins arranged as 2-D crystals without requiring cryogenic conditions or the formation of three-dimensional crystals.

Development of Cation-Dependent Layer to Layer Intermolecular Correlations in 5-Bilayer Arachidic Acid Multilayers

1990 ◽  
Vol 208 ◽  
Author(s):  
Robert F. Fischetti ◽  
Songtao Xu ◽  
J. Kent Blasie
Keyword(s):  
Ph Value ◽  
Function Analysis ◽  
Arachidic Acid ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Correlation Lengths ◽  
X Ray ◽  
Patterson Function ◽  
Glass Substrates ◽  
Diffraction Patterns

ABSTRACTWe have recorded two-dimensional X-ray diffraction patterns from fivebilayer Langmuir-Blodgett multilayer films. The films were deposited on alkylated glass substrates from monolayers of arachidic acid which were spread on barium or cadmium cation containing subphases: the pH was systematically varied from 4 to 9. The diffraction patterns were recorded using doubly-focusing X-ray optics and a two-dimensional position sensitive detector.Generalized Patterson function analysis of the meridional X-ray diffraction I (qxy = 0, qz), which arises from the profile structure of the multilayer, indicated that the bilayer to bilayer correlations improved with increasing pH value (i.e., with incorporation of divalent metal cations into the film). Experimentally determined electron density profiles have previously shown that the average in-plane density of the down-stroke monolayers was greater than that of the the up-stroke monolayers, in agreement with the observed transfer ratios.We observed Bragg rods at several qxy-values only for multilayers for which the subphase was of intermediate to high pH. The intensity and degree of sampling of the Bragg rods along qz increased with increasing pH value. At the highest pH values, the in-plane intermolecular correlation lengths were ∼600 Å and the bilayer to bilayer intermolecular correlation lengths were ∼165 Å or ∼2 1/2 bilayers. This indicates that for the fatty-acid salts the monolayers of low average in-plane density are “patched” with separated domains which have been deposited epitaxially on the underlying monolayers of high average inplane density.

scholarly journals Single-shot full strain tensor determination with microbeam X-ray Laue diffraction and a two-dimensional energy-dispersive detector

2017 ◽  
Vol 50 (3) ◽  
pp. 901-908 ◽  
Author(s):  
A. Abboud ◽  
C. Kirchlechner ◽  
J. Keckes ◽  
T. Conka Nurdan ◽  
S. Send ◽  
...  
Keyword(s):  
Elastic Strain ◽  
Strain Tensor ◽  
Energy Dispersive ◽  
Single Shot ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Laue Diffraction ◽  
Experimental Procedure ◽  
X Ray ◽  
Diffraction Patterns

The full strain and stress tensor determination in a triaxially stressed single crystal using X-ray diffraction requires a series of lattice spacing measurements at different crystal orientations. This can be achieved using a tunable X-ray source. This article reports on a novel experimental procedure for single-shot full strain tensor determination using polychromatic synchrotron radiation with an energy range from 5 to 23 keV. Microbeam X-ray Laue diffraction patterns were collected from a copper micro-bending beam along the central axis (centroid of the cross section). Taking advantage of a two-dimensional energy-dispersive X-ray detector (pnCCD), the position and energy of the collected Laue spots were measured for multiple positions on the sample, allowing the measurement of variations in the local microstructure. At the same time, both the deviatoric and hydrostatic components of the elastic strain and stress tensors were calculated.

DATAD: a Python-based X-ray diffraction simulation code for arbitrary texture and arbitrary deformation

2021 ◽  
Vol 54 (2) ◽  
pp. 686-696
Author(s):  
J. W. Huang ◽  
Y. Y. Zhang ◽  
S. C. Hu ◽  
Y. Cai ◽  
S. N. Luo
Keyword(s):  
Single Crystal ◽  
Applied Strain ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Simulation Code ◽  
Polycrystalline Specimen ◽  
Basic Principles ◽  
X Ray ◽  
Deformation State ◽  
Diffraction Patterns

DATAD, a Python-based X-ray diffraction simulation code, has been developed for simulating one- and two-dimensional diffraction patterns of a polycrystalline specimen with an arbitrary texture under an arbitrary deformation state and an arbitrary detection geometry. Pixelated planar and cylindrical detectors can be used. The basic principles and key components of the code are presented along with the usage of DATAD. As validation and application cases, X-ray diffraction patterns of single-crystal and polycrystalline specimens with or without texture, or applied strain, on a planar or cylindrical detector are simulated.

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