Crystallography in Open Science and its open educational resources

Open Science is the movement to make scientific research, the data and their dissemination available to any member of an inquiring society, from professionals to citizens, irrespective of their economic situation. The IUCr provides fully open educational resources to Global South and Global North readers and authors.

MIDAS: a methodological framework for high-speed high-energy diffraction microscopy data reduction. Part I: methodology

This paper details the complete methodological framework implemented in the MIDAS software for processing high-energy diffraction microscopy (HEDM) data. We describe the specific algorithms, coordinate systems and physical models used for both far-field and near-field HEDM analysis. The framework is designed to handle the large and complex datasets from modern synchrotrons, enabling efficient and accurate extraction of microstructural information.

From atoms to a data bank: optimizing transferability of electron-density symmetry

This work focuses on the electron density of atoms modeled with a multipolar approach. We investigate how the refinement of the multipole models with/without symmetry constraints and optimization of the orientation of the local coordinate system and pseudosymmetry assignment improves the accuracy of electron-density representations for atoms and atom types in a pseudoatom data bank.

New algorithm for generating all coincidence-site lattices of the cubic crystal system

We present a simple linear-algebra-based condition for identifying all coincidence-site lattice orientation relationships in cubic crystals by testing the commensurability of (hkl) planes with (001).

Symmetries of a dynamical system arising from a biquadratic number field

The study characterizes the symmetries of a symbolic dynamical system arising from k-free integers in the biquadratic field . It proves that the extended symmetry group is a semi-direct product , with the stabilizer explicitly linked to the field's unit and Galois groups. The analysis demonstrates how these number-theoretic shifts mirror the complex symmetry structures typically seen in aperiodic order.

Renormalization techniques for inflation systems and some of their applications

In this work, renormalization methods for quantities related to the diffraction of inflation systems are surveyed.

MIDAS: a qu­antitative framework for high-energy diffraction microscopy. Part II: accuracy, robustness and best practices

This paper experimentally establishes the accuracy, robustness and performance limits of the high-energy diffraction microscopy data reduction methodology. Using dedicated far-field and near-field datasets, it quantifies the influence of key analysis parameters, demonstrates computational efficiency, and establishes a framework of best practices to guide the community towards more reproducible results.

Beyond complementarity: a reverse-engineering framework for de novo crystal structure determination from EXAFS

This study introduces and validates a novel methodological paradigm that transforms extended X-ray absorption fine structure (EXAFS) spectroscopy from a complementary local probe into a primary, stand-alone tool for determining complete crystal structures.

Case study of using the single-atom R1 method to solve a small protein structure

A small protein structure has been successfully solved by the single-atom R1 method after accounting for the hidden solvent diffraction effects.

A real rhombic dodecahedron: morphology and crystal shape variations

We discuss a method for describing the geometry and habit of distorted rhombic dodecahedral crystals. The proposed method serves as the basis for analyzing the relationship between the asymmetry of the environment and the mineral individuals of crystals of a wide variety of shapes in any distortion range.

Twenty-Sixth General Assembly and International Congress of Crystallography, Melbourne, Australia, 22–29 August 2023

Graphs and Homomorphisms