forthcoming articles

Strain in GaN/AlN SLs decreases with increasing well/barrier thickness. Interface quality impacts SL properties, with optimal results at 3 nm. The quantum-confined Stark effect causes red-shift in PL spectra, confirmed by DFT calculations. Understanding strain and defects crucial for GaN/AlN SL device design.

In our study, we used theoretical quantum crystallography (QCr) methods to analyze the electron density and bonding nature of Ca-sc under extreme pressures, up to 40 GPa. Through these techniques, we have studied the electronic structure through the pressure induced electronic transitions and when the multi-center bonding (MCB) formation characteristics emerge in this HPE, leveraging the chemical information that can be extracted from the topological analysis of the electron density and the indirect measurements of atomic electronegativities. These findings demonstrate the capability of QCr to reveal the complex bonding and electronic structures of HPEs, which have so far largely been studied through theoretical models alone. This work highlights the broader applicability of QCr in HPE research, addressing the challenges in experimentally validating these phases due to the difficulty of making direct observations under high-pressure conditions. The combination of quantum computational and crystallographic data, facilitated by QCr, could bridge the gap between theoretical predictions and experimental validation, enabling a more comprehensive understanding of materials in extreme environments. [Please reduce to 1-2 sentences]

One hundred years after the quantum theory established position and momentum as incompatible quantities, quantum crystallography offers a way to visualize electron phase space behaviour in crystals.

At 623 K, the thermovapour treatment of calcium and tin oxides leads to the formation of the previously unknown CaSn₂O₄(OH)₂ lamellar crystals. This phase is stable up to 973 K and has high catalytic activity and selectivity to C₆₊ products in the aldol condensation of acetone.

High-resolution single-crystal X-ray diffraction experiments were performed for Sm₂Mn_1–xGa_6–yGe_y over a wide temperature range (180–430 K). The experiments revealed significant strucural changes that are caused by structural disorder and magnetic ordering.

Four novel benzyl­amine-based crown ether inclusion com­plexes have been synthesized, [(4-XBA)(18-crown-6)][DMSA] [X = F, Cl, Br and I; BA= benzyl­amine; DMSA = di(methane­sulfony)amidate]. The effects of the different halogen atoms on the stacking within the crystals of the com­plexes are described.

The supra­molecular inter­actions and Hirshfeld surfaces of three multicom­ponent systems, namely, 2,4-di­amino-6-phenyl-1,3,5-tri­a­z­ine–nicotinic acid, 2,4-di­amino-6-phenyl-1,3,5-triazin-1-ium hy­dro­gen malonate and 2,4-di­amino-6-phenyl-1,3,5-triazin-1-ium hy­dro­gen (+)-dibenzoyl-D-tartarate have been investigated.

The ability to control the yield for a [2+2] cyclo­addition photoreaction by using a mixed cocrystal approach is reported. The two isosteric halogen-bond donors allow for the formation of the cocrystal solid solution and as a result influences the extent of the photoreaction based upon their initial molar ratios.

The crystal structure of capsaicin, the natural product responsible for the pungency of chilli peppers, was determined by low-temperature single-crystal X-ray diffraction.

There are very few examples of crystallographically well-documented racemic mimics. Therefore, this inter­esting class of crystalline mol­ecules, potentially having useful biological uses, is today one of those scientific orphans largely ignored in the crystallographic realm. Some suggestions are provided for searching for potential cases of such a crystallization mode using information already in print.

Cryo-EM density map inference, with fixed pose and CTF, using a multi-resolution hash-encoding framework called instant-NGP. Extension to heterogeneity inference by bending space with a per-image vector field.

A global analysis of protein crystal structures in the Protein Data Bank (PDB) reveals many pairs with (nearly) identical main-chain coordinates. Such cases are identified and analyzed, leading to a proposal about how the PDB could ameliorate the problem.

The crystal structure is characterized by a three-dimensional hydrogen-bonding network. Chains formed through N—H⋯O contacts are linked by additional inter­molecular bonds to complete the structure.

The structure of a tris­(2-methyl-1H-imidazol-3-ium) di­hydrogenetrimesate⁻ mono­hydrogentrimesate²⁻ compound was determined by single-crystal X-ray diffraction. The compound is mixture of protonated and deprotonated mol­ecules.

Mol­ecules (1), (2), (3) and (5) adopt a Z configuration with respect to the central C=N bond, while (4) adopts an E configuration.

Tetra­oxa[2]perfluoro­arene[2]triazine (C₂₀H₆F₈N₆O₆), composed of two tetra­fluoro­phenyl­ene and two triazine moieties connected by four oxygen atoms, was crystallized via slow evaporation of a di­chloro­methane solution, yielding two polymorphs with block- and plate-shaped crystals.

The title compound contains pyran and phenyl rings, with the pyran ring in a flattened-boat conformation. In the crystal, inter­molecular N—H⋯N hydrogen bonds link the mol­ecules into centrosymmetric dimers, forming R²₂(12) ring motifs, which are linked by N—H⋯O hydrogen bonds into a three-dimensional architecture. In addition to van der Waals inter­actions and N—H⋯N and N—H⋯O hydrogen bonds, halogen bonds, tetrel bonds and pnictogen bonds also play an important role in the cohesion of the crystal structure.

The purification, crystallization, and structure at 1.95 Å resolution of cyclophilin 37 (CYP37) from Arabidopsis thaliana (AtCYP37) is reported. The structure, which is similar to AsCYPA and AtCYP38, is crucial for understanding how AtCYP37 interacts with the PetA subunit in Cyt b₆f, which is involved in the photoprotective mechanism of plants under high light conditions.

Peptide deformylases (PDFs) have been of interest as viable drug targets for the development of new antimicrobials. Two crystal structures of PDF from Legionella pneumophila serogroup 1, the causative agent of Legionnaires' disease, bound to Ni²⁺ or actinonin and Zn²⁺, were solved to 1.5 and 1.65 Å resolution, respectively.

High-throughput protein crystallography is used at the heart of a pipeline to accelerate the discovery of bioactive natural products by capturing these hits with protein crystals directly from unpurified biota samples.

The crystal structure of UmaA from M. tuberculosis was solved to 1.95 Å resolution in space group P3₂21.

This study tunes the energy landscape of the st-PMMA/C₆₀/toluene complex system and finds the efficient pathway to form the thermodynamically favored st-PMMA/C₆₀ complex by temperature modulation. This st-PMMA/C₆₀ complex architecture further acts as a photoreduction site for yielding the Ag SERS-active substrate for advanced chemical sensing applications.

Small-angle X-ray scattering technique was applied to polyether polyurethane (PU) to investigate the effects of solvent vapor annealing on the microphase separation. Among the solvents studied, methyl ethyl ketone induced the greatest degree of phase separation in PU compared with the thermally annealed state.

Upgrades at the KWS-2 SANS diffractometer for an optimal sample quality for biological systems (in-beam SEC complementarity), controlled humidity and temperature on ionic conductive samples and biological membranes and diffraction capability (WANS) are reported.

The complete maximal subgroups of subperiodic groups database of the Bilbao Crystallographic Server is presented. The program MAXSUB gives online access to all maximal non-isotypic as well as all maximal isotypic subgroups of indices up to 9, and to the series of maximal isotypic subgroups of subperiodic groups.

This article reports non-destructive 3D texture mapping of a wide range of polycrystalline materials using synchrotron X-rays and utilizing the sparsity of the reconstructed texture.

Three multicomponent crystals of the form MCl:Urea·xH₂O (M = Li, Na, Cs) have been prepared with novel mechanochemical methods, and their crystal structures determined using an NMR crystallography-guided Rietveld refinement that features the combined use of multinuclear solid-state NMR of quadrupolar nuclei, plane-wave density functional theory calculations and synchrotron powder X-ray diffraction data.

A far-field laboratory diffraction contrast tomography (FF-LabDCT) technique is established and verified using conventional near-field LabDCT. Future directions to enhance FF-LabDCT as a versatile tool are outlined.

The present work provides a simple method to obtain the chemical unit of a solid-solution alloy directly using Cowley's short-range-order parameters α₁ and α₂.

This article presents an application of X-ray photon correlation spectroscopy (XPCS) to probe the out-of-equilibrium dynamics in a driven colloidal system. XPCS enables the investigation of direction-dependent non-equilibrium dynamics and the gradual return of the suspension to equilibrium Brownian behaviour. The influence of such transient non-equilibrium dynamics needs to be taken into consideration when dynamic scattering methods are used for micrometre-range particle measurement.

A scalable forward model is developed to calculate virtual dark-field X-ray microscopy (DFXM) images of complex dislocation structures predicted by atomistic simulations, demonstrating the potential of DFXM to resolve features from dislocation multiplication and microstructural evolution.

We describe the first implementation of an operando transmission X-ray microscopy to study laser melting at X-ray free-electron lasers. Our instrument used a novel pump-probe-probe scheme to image down to 940 nm spatial resolution with integration times <100 fs and up to 0.48 GHz frame rates to study the rapid dynamics and small-scale features in laser additive manufacturing.

The BM02/D2AM beamline at the ESRF is shown to be suitable to perform X-ray Photon Correlation Spectroscopy (XPCS) experiments with a flux that prevents sample's irradiation effects, features particularly suitable for polymer-based materials.

A new X-ray spectrometer for high photon energies based on Laue analyzer crystals is presented. Its performance in terms of energy resolution and efficiency is discussed. Niobium Kα and Kβ emission data collected with this Laue spectrometer are given.

The Structural Biology Research Center at the High Energy Accelerator Research Organization has developed advanced systems for macromolecular crystallography, including an automated crystallization screening system, a long-wavelength crystallography beamline and an automated data-collection system.

The performance of the High Energy beamline of the Brockhouse Sector of the Canadian Light Source is described in terms of flux, bandwidth, divergence, and focus of the beam. Its uses include high energy penetrating diffraction, high pressure diffraction, and pair distribution function studies.

The OÆSE endstation on EMIL at the BESSY II synchrotron facility in Berlin allows real-time investigation of energy materials through operando X-ray absorption spectroscopy. The possibility to use soft, tender and hard X-rays combined with versatile operando sample environments enables the study of a wide range of energy materials under relevant operation conditions.

The history, current state and future directions of the three MX beamlines BL14.1, BL14.2 and BL14.3 of the Helmholtz-Zentrum Berlin at the BESSY II electron storage ring are described.

The XRD2 beamline at Elettra-Sincrotrone Trieste has been in operation since 2018 and is dedicated to macromolecular crystallography for both academic and industrial research, a role partially fulfilled, before 2018, by XRD1, a general-purpose diffraction beamline. With the upcoming Elettra 2.0 upgrade, based on a six-bend enhanced achromat lattice, the synchrotron will offer a brighter, more powerful beam to address evolving challenges in crystallography.

High resolution crystal structures reveal that peptide bonds in α-helices exhibit a slightly more pronounced enol-like character than those in β-strands. This can go as far as peptide oxygen atoms in protein structures being protonated.

The development of Quantum Crystallography rests on the availability of reliable theoretical electron densities. This work demonstrates a non-negligible code-dependence of these densities and warns about their blind use.

A review of plane-wave coherent X-ray diffraction imaging in small-angle X-ray scattering geometry is presented, together with a discussion of the new opportunities offered by fourth-generation synchrotron sources.

Developments in macromolecular crystallography now allow the use of microcrystals for structural analysis through advanced beamlines and techniques such as microcrystal electron diffraction and room-temperature crystallography. This review addresses methods of matching microcrystal preparation and sample delivery. The use of microcrystals enhances the possibilities in fields such as time-resolved crystallography.

This study establishes that hydrogen-, halogen- and chalcogen-bonding intermolecular and non-covalent intramolecular interactions are driven by a face-to-face orientation of electrophilic (charge-depleted) and nucleophilic (charge-concentrated) regions, being at the origin of the specific geometries found in synthons and supramolecular motifs.

The synthesis and single-crystal structure description of a silver(I) diphenyl-2-meth­oxy­phenyl­phosphine nitrite complex is described.

The crystal structure of an arene ruthenium(II) complex bearing a bidentate Schiff base ligand is reported.