Findable Accessible Interoperable Re-usable (FAIR) diffraction data are coming to protein crystallography

The policy of IUCr Journals on diffraction data is defined.

Exploiting the potential of beam-compressing channel-cut monochromators for laboratory high-resolution small-angle X-ray scattering experiments

A comprehensive approach to the targeted design of channel-cut X-ray monochromators taking into account the real source divergence is presented. A compressing crystal monochromator with a strongly asymmetric V-shaped channel designed in this way improved the small-angle X-ray scattering resolution by 2.5 times compared with pinhole collimation and exhibits more than one order higher transmittance than a Kratky collimator at the same resolution.

Small-angle scattering by supported nanoparticles: exact results and useful approximations

Nanoparticles are often dispersed on a porous support, which makes their analysis by small-angle scattering challenging. Exact expressions for the scattering contributions from the particles, from the support and from their cross-correlation are derived, as well as some approximations useful for data analysis.

A practical approach to the direct-derivation method for QPA: use of observed powder patterns of individual components without background subtraction in whole-powder-pattern fitting

In a new approach to whole-powder-pattern fitting, observed diffraction patterns are used as the fitting functions without subtracting their background intensities. This simple procedure allows stable least-squares refinement and gives accurate results in quantitative phase analysis (QPA). The theoretical basis and experimental verifications of the procedure are given.

Non-edge-triggered inversion from Ga polarity to N polarity of c-GaN domains on an SiO₂ mask during epitaxial lateral overgrowth

Polarity inversion from Ga polarity to N polarity of m-facet-exposed c-GaN domains is observed to occur during epitaxial lateral overgrowth on the flat region beyond the edge of a circular-patterned SiO₂ mask. An increased flow rate of NH₃ during the epitaxial lateral overgrowth is thought to induce this type of non-edge-triggered polarity inversion. The control of inversion domain boundaries can provide another degree of freedom in growing mixed-polarity periodic structures.

Model-independent recovery of interfacial structure from multi-contrast neutron reflectivity data

An indirect Fourier transform/simulated annealing method exploits the information content of multiple solvent contrast neutron reflectivity data and permits the model-independent recovery of interfacial structure at the air/liquid and solid/liquid interface.

Estimation of geometrically necessary dislocation density from filtered EBSD data by a local linear adaptation of smoothing splines

An implementation of smoothing splines allowing for an intuitive calibration of the fitting versus smoothing trade-off and directly applicable to any grid/neighbourhood is proposed to reduce orientation noise in electron backscatter diffraction (EBSD) data, and subsequently estimate more accurate geometrically necessary dislocation (GND) densities. In particular, the local linear adaptation of smoothing splines filter reasonably preserves sub-boundaries and GND structures.

Vapour growth, morphology, absolute structure and pyroelectric coefficient of meta-nitro­aniline single crystals

The vapour growth speed R of different faces of meta-nitro­aniline crystals is nearly isotropic. An absolute structure determination and scanning pyroelectric microscopy confirm mono-domain polar crystals. The material shows a positive pyroelectric coefficient.

Qu­antitative nanotomography of amorphous and polycrystalline samples using coherent X-ray diffraction

An approach to characterizing the mass density, nanoscale morphology and crystallinity of an isolated microscopic specimen is presented. The method combines coherent diffraction imaging and crystal diffraction in one experiment.

Thermally induced transformations of Au@Cu₂O core–shell nanoparticles into Au–Cu nanoparticles from temperature-programmed in situ powder X-ray diffraction

Reaction pathways in the formation of multimetallic nanoparticles are investigated through in situ powder X-ray diffraction.

Full-profile search–match by the Rietveld method

A new fully automatic search–match procedure based on a Rietveld full-pattern-fitting method is presented. The method does not rely on peak positions and permits not only phase identification but also a quantification of the phases and their gross microstructural features.

Characterization of ammonium di­hydrogen phosphate crystals for soft X-ray optics of the Beam Expander Testing X-ray facility (BEaTriX)

A crystal of ammonium dihydrogen phosphate is characterized with respect to its crystallographic quality and the presence of residual strain. The crystal quality is fundamental in view of its use in the BEaTriX X-ray facility for testing silicon pore optics modules of the ATHENA X-ray telescope.

Varieties of 12-fold rosettes and their applications in Moroccan geometric ornament

This article is devoted to the study of 12-fold rosettes. A simple method to build new patterns with different types of 12-fold rosettes and their variants is proposed. A procedure, based on combination of the distances between overlapping 12-fold rosettes, to generate new periodic and quasiperiodic patterns is also presented.

Raman Open Database: first interconnected Raman–X-ray diffraction open-access resource for material identification

The fully open character of the Raman Open Database makes this novel database freely and completely usable by anybody worldwide: academics, those working in industry and the general public.

Precession electron diffraction tomography on twinned crystals: application to CaTiO₃ thin films

Electron diffraction is used to obtain accurate structural parameters from thin films by taking into account the presence of twinning.

Detailed surface analysis of V-defects in GaN films on patterned silicon(111) substrates by metal–organic chemical vapour deposition

This is a detailed study on a common type of defect in GaN materials. The data and results are important for the growth and application of GaN materials.

3D grain reconstruction from laboratory diffraction contrast tomography

A novel reconstruction method to retrieve grain structure from laboratory diffraction contrast tomography is presented and evaluated.

Diffuse + Bragg double scattering and specular reflection observed in the small-angle X-ray scattering from highly oriented pyrolytic graphite

Diffuse + Bragg double scattering and specular reflection are observed in the small-angle X-ray scattering from as-prepared and neutron-irradiated highly oriented pyrolytic graphite samples. The scattering from the neutron-irradiated sample shows oscillatory behavior, and this indicates that it has a slab-like structure.

An introduction to classical molecular dynamics simulation for experimental scattering users

This work introduces an interactive open educational resource aimed at introducing users of elastic scattering techniques to classical molecular dynamics simulation and showing how the simulation may be used to inform the experimental analysis.

PDB2INS: bridging the gap between small-molecule and macromolecular refinement

PDB2INS reads a Protein Data Bank (PDB)-format file and writes a .ins file containing the atom data and instructions for SHELXL refinement. Given only the PDB code of a deposited structure, it automatically creates both files (.ins and .hkl) necessary to refine the structure.

ClickX: a visualization-based program for preprocessing of serial crystallography data

A Python-based program for serial crystallography experimental data preprocessing is developed for both online and offline analysis. Enhanced features include a graphical user interface, batch job execution and fast parameter optimizations.

GIDVis: a comprehensive software tool for geometry-independent grazing-incidence X-ray diffraction data analysis and pole-figure calculations

GIDVis is a software package based on MATLAB which is specialized for the visualization and analysis of grazing-incidence thin-film X-ray diffraction data obtained during sample rotation around the surface normal. Using GIDVis, detector calibration, data stitching, intensity corrections, cuts and integrations, crystal phase analysis, and calculation of pole figures can be easily performed.

DebyeFit: a simple tool to obtain an appropriate model of atomic vibrations in solids from atomic displacement parameters obtained at different temperatures

DebyeFit is a computer program that calculates the Debye/Einstein characteristic temperature of atomic vibrations in solids using equivalent atomic displacement parameters (ADPs) determined at several temperatures. An optimal fit is achieved if ADPs are modeled with both static and dynamic components.

Comment on the article The nanodiffraction problem

The article The nanodiffraction problem [Xiong, Öztürk, Lee, Mooney & Noyan (2018). J. Appl. Cryst. 51, 1102–1115] is discussed.

Response to Zbigniew Kaszkur's comment on the article The nanodiffraction problem

A response to the comment by Kaszkur [J. Appl. Cryst. (2019), 52, 693–694].

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