Integrated edge-to-exascale workflow for real-time steering in neutron scattering experiments.

We introduce a computational framework that integrates artificial intelligence (AI), machine learning, and high-performance computing to enable real-time steering of neutron scattering experiments using an edge-to-exascale workflow. Focusing on time-of-flight neutron event data at the Spallation Neutron Source, our approach combines temporal processing of four-dimensional neutron event data with predictive modeling for multidimensional crystallography. At the core of this workflow is the Temporal Fusion Transformer model, which provides voxel-level precision in predicting 3D neutron scattering patterns.

Neutron Instruments for Research in Coordination Chemistry.

Neutron diffraction and spectroscopy offer unique insight into structures and properties of solids and molecular materials. All neutron instruments located at the various neutron sources are distinct, even if their designs are based on similar principles, and thus, they are usually less familiar to the community than commercial X-ray diffractometers and optical spectrometers. Major neutron instruments in the USA, which are open to scientists around the world, and examples of their use in coordination chemistry research are presented here, along with a list of similar instruments at main neutron facilities in other countries.

Giant Modulation of Refractive Index from Picoscale Atomic Displacements.

It is shown that structural disorder-in the form of anisotropic, picoscale atomic displacements-modulates the refractive index tensor and results in the giant optical anisotropy observed in BaTiS, a quasi-1D hexagonal chalcogenide. Single-crystal X-ray diffraction studies reveal the presence of antipolar displacements of Ti atoms within adjacent TiS chains along the c-axis, and threefold degenerate Ti displacements in the a-b plane. Ti solid-state NMR provides additional evidence for those Ti displacements in the form of a three-horned NMR lineshape resulting from a low symmetry local environment around Ti atoms.

(+)-Cedrol hemihydrate: a natural product derived from drying eastern red cedar (Juniperus virginiana) wood.

Cedrol-like compounds are of pharmacological interest due to their diverse range of medicinal effects and are used globally in traditional medicines and cosmetics. Many cedrol tautomers are known from molecular studies but few have been studied in crystalline form by X-ray diffraction. Acicular white crystals collected from the wood of eastern red cedar (Juniperus virginiana) are determined to be (+)-cedrol hemihydrate, namely, (1S,2R,5S,7R,8R)-2,6,6,8-tetramethyltricyclo[5.

Benchmark Crystal Structure of Defect-Free Spinel ZnFeO.

Accurate structural models are of paramount importance for elucidating structure-property relationships in functional materials. Spinels (ABO) form a highly important family of materials with complex crystal structures, and subtle structural details have a critical bearing on understanding their physical properties. In some spinels, the space group symmetry is debated, and in general, point defects such as cation inversion and interstitials add complexity.

Charge Density Wave Order and Electronic Phase Transitions in a Dilute d-Band Semiconductor.

As one of the most fundamental physical phenomena, charge density wave (CDW) order predominantly occurs in metallic systems such as quasi-1D metals, doped cuprates, and transition metal dichalcogenides, where it is well understood in terms of Fermi surface nesting and electron-phonon coupling mechanisms. On the other hand, CDW phenomena in semiconducting systems, particularly at the low carrier concentration limit, are less common and feature intricate characteristics, which often necessitate the exploration of novel mechanisms, such as electron-hole coupling or Mott physics, to explain. In this study, an approach combining electrical transport, synchrotron X-ray diffraction, and density-functional theory calculations is used to investigate CDW order and a series of hysteretic phase transitions in a dilute d-band semiconductor, BaTiS .

Colossal Optical Anisotropy from Atomic-Scale Modulations.

Materials with large birefringence (Δn, where n is the refractive index) are sought after for polarization control (e.g., in wave plates, polarizing beam splitters, etc.

Direct Visualization of Magnetic Correlations in Frustrated Spinel ZnFe O.

Magnetic materials with the spinel structure (A B O ) form the core of numerous magnetic devices, and ZnFe O constitutes a peculiar example where the nature of the magnetism is still unresolved. Susceptibility measurements revealed a cusp around T  = 13 K resembling an antiferromagnetic transition, despite the positive Curie-Weiss temperature determined to be Θ  = 102.8(1) K.

PIONEER, a high-resolution single-crystal polarized neutron diffractometer.

PIONEER is a high Q-resolution, single-crystal, polarized neutron diffractometer at the Second Target Station (STS), Oak Ridge National Laboratory. It will provide the unprecedented capability of measuring tiny crystals (0.001 mm, i.

Quantifying fish otolith mineralogy for trace-element chemistry studies.

Otoliths are frequently used to infer environmental conditions or fish life history events based on trace-element concentrations. However, otoliths can be comprised of any one or combination of the three most common polymorphs of calcium carbonate-aragonite, calcite, and vaterite-which can affect the ecological interpretation of otolith trace-element results. Previous studies have reported heterogeneous calcium carbonate compositions between left and right otoliths but did not provide quantitative assessments of polymorph abundances.

: reverse Monte Carlo refinement of diffuse scattering and correlated disorder from single crystals.

A user-friendly program has been developed to analyze diffuse scattering from single crystals with the reverse Monte Carlo method. The approach allows for refinement of correlated disorder from atomistic supercells with magnetic or structural (occupational and/or displacive) disorder. The program is written in Python and optimized for performance and efficiency.

Influence of ontogenetic development, temperature, and pCO on otolith calcium carbonate polymorph composition in sturgeons.

Changes to calcium carbonate (CaCO) biomineralization in aquatic organisms is among the many predicted effects of climate change. Because otolith (hearing/orientation structures in fish) CaCO precipitation and polymorph composition are controlled by genetic and environmental factors, climate change may be predicted to affect the phenotypic plasticity of otoliths. We examined precipitation of otolith polymorphs (aragonite, vaterite, calcite) during early life history in two species of sturgeon, Lake Sturgeon, (Acipenser fulvescens) and White Sturgeon (A.

Morphology and composition of Goldeye (Hiodontidae; Hiodon alosoides) otoliths.

We provide up-to-date morphological and compositional data on otoliths of the osteoglossomorph Goldeye (Hiodon alosoides). Using computed tomography (CT) X-ray, we documented the location of each of the three pairs of otoliths (lapilli, sagittae, and asterisci) in relation to the swim bladder, which extended forward in close proximity to the sagittae and asterisci. The lappili were the largest otoliths in terms of surface area and volume, but the sagittae were highly modified, appearing spiral in shape when viewed dorsally, with a surface area to volume ratio more than double that of the lapilli.

Texture Analysis of Polycrystalline Vaterite Spherulites from Lake Sturgeon Otoliths.

Fish otoliths, or ear bones, are comprised of the CaCO polymorphs (aragonite, calcite and vaterite), which can occur either alone or in combination. The polymorph phase abundance in an otolith depends on, as yet, unexplained genetic and environmental factors. Most fish otoliths are comprised of the densest CaCO polymorph, aragonite.

Otoliths of sub-adult Lake Sturgeon Acipenser fulvescens contain aragonite and vaterite calcium carbonate polymorphs.

In this study we quantified the percent CaCO polymorph composition in otoliths of larval and juvenile Lake Sturgeon Acipenser fulvescens via X-ray microdiffraction. Sagittal otoliths of sub-adults were primarily composed of aragonite (> 90%) while the lapilli otoliths were 100% vaterite. This is the first time the presence of aragonite in otoliths has been reported in an acipenseriform and is surprising given that the ability to form aragonite otoliths was not thought to have evolved until the separation of teleost and holostean species from other Actinopterygian fishes (e.

Model-free reconstruction of magnetic correlations in frustrated magnets.

Frustrated magnetic systems exhibit extraordinary physical properties, but quantification of their magnetic correlations poses a serious challenge to experiment and theory. Current insight into frustrated magnetic correlations relies on modelling techniques such as reverse Monte-Carlo methods, which require knowledge about the exact ordered atomic structure. Here, we present a method for direct reconstruction of magnetic correlations in frustrated magnets by three-dimensional difference pair distribution function analysis of neutron total scattering data.

Giant magnetoelectric effects achieved by tuning spin cone symmetry in Y-type hexaferrites.

Multiferroics materials, which exhibit coupled magnetic and ferroelectric properties, have attracted tremendous research interest because of their potential in constructing next-generation multifunctional devices. The application of single-phase multiferroics is currently limited by their usually small magnetoelectric effects. Here, we report the realization of giant magnetoelectric effects in a Y-type hexaferrite BaSrMgFeO single crystal, which exhibits record-breaking direct and converse magnetoelectric coefficients and a large electric-field-reversed magnetization.

Empirically testing vaterite structural models using neutron diffraction and thermal analysis.

Otoliths, calcium carbonate (CaCO) ear bones, are among the most commonly used age and growth structures of fishes. Most fish otoliths are comprised of the most dense CaCO polymorph, aragonite. Sturgeon otoliths, in contrast, have been characterized as the rare and structurally enigmatic polymorph, vaterite-a metastable polymorph of CaCO.

The IMAGINE instrument: first neutron protein structure and new capabilities for neutron macromolecular crystallography.

The first high-resolution neutron protein structure of perdeuterated rubredoxin from Pyrococcus furiosus (PfRd) determined using the new IMAGINE macromolecular neutron crystallography instrument at the Oak Ridge National Laboratory is reported. Neutron diffraction data extending to 1.65 Å resolution were collected from a relatively small 0.

Spin reorientation in TlFe1.6Se2 with complete vacancy ordering.

The relationship between vacancy ordering and magnetism in TlFe(1.6)Se(2) has been investigated via single crystal neutron diffraction, nuclear forward scattering, and transmission electron microscopy. The examination of chemically and structurally homogeneous crystals allows the true ground state to be revealed, which is characterized by Fe moments lying in the ab plane below 100 K.

New family of cerium halide based materials: CeX3·ROH compounds containing planes, chains, and tetradecanuclear rings.

Six members of a new family of cerium-halide-based materials with promising scintillation behavior have been synthesized in single crystal form, and their crystal structures were determined. Specifically, these new compounds are [(CeCl(3))(7)(BuOH)(16)(H(2)O)(2)]·(BuOH)(2) (1), (CeBr(3))(14)(BuOH)(36) (2), [(CeCl(3))(7)(1-PrOH)(16)(H(2)O)(2)]·(1-PrOH)(2) (3), [(CeBr(3))(7)(1-PrOH)(18)]·(1-PrOH)(2) (4), [(CeCl(3))(6)(iBuOH)(15)]·(iBuOH)(2) (5), and CeCl(3)(sec-BuOH)(2)(H(2)O) (6). Additionally, the scintillation ability of compound 1 was established.

Neutron diffraction study of the type I clathrate Ba8Al(x)Si(46-x): site occupancies, cage volumes, and the interaction between the guest and the host framework.

Samples with the type I clathrate structure and composition Ba(8)Al(x)Si(46-x), where x = 8, 10, 12, 14, and 15, were examined by neutron powder diffraction at 35 K. The clathrate type I structure contains Ba cations as guests in a framework derived from tetrahedrally coordinated Al/Si atoms. The framework is made up of five- and six-membered rings that form dodecahedral and tetrakaidecahedral cages.

Direct experimental evidence for atomic tunneling of europium in crystalline Eu8Ga16Ge30.

Mössbauer-effect and microwave absorption experimental evidence unambiguously demonstrates the presence of slow, approximately 450 MHz, tunneling of magnetic europium between four equivalent sites in Eu8Ga16Ge30, a stoichiometric clathrate. Remarkably, six of the eight europium atoms, or 11% of the constituents in this solid, tunnel between these four sites separated by 0.55 A.