We describe a model-independent approach for the extraction of detailed lattice dynamics information from neutron powder diffraction data, based on a statistical analysis of atomistic configurations generated using reverse Monte Carlo structural refinement. Phonon dispersion curves for MgO extracted in this way are shown to reproduce many of the important features found in those determined inde...

Neutron diffraction has proven to be an indispensable and highly significant tool since its development 60 years ago. The neutron has unique properties that yield distinct information unavailable otherwise. Chief among these properties is the relative uniformity of the neutron scattering power of atoms across the periodic table, allowing the accurate structure determination of materials compose...

The specific heat of Ce3Co4Sn13 exhibits a crossover from heavy Fermion behavior with antiferromagnetic correlations at low field to single impurity Kondo behavior above 2T. We have performed neutron diffraction measurements in magnetic fields up to 6T on single crystal samples. The (0 0 1) position shows a dramatic increase in intensity in field which appears to arise from static polarization ...

Otoliths, calcium carbonate (CaCO3) ear bones, are among the most commonly used age and growth structures of fishes. Most fish otoliths are comprised of the most dense CaCO3 polymorph, aragonite. Sturgeon otoliths, in contrast, have been characterized as the rare and structurally enigmatic polymorph, vaterite-a metastable polymorph of CaCO3. Vaterite is an important material ranging from biomed...

X-ray diffraction data cannot provide anisotropic displacement parameters (ADPs) for H atoms, a major outstanding problem in charge-density analysis of molecular crystals. Although neutron diffraction experiments are the preferred source of this information, for a variety of reasons they are possible only for a minority of materials of interest. To date, approximate procedures combine rigid-bod...

We discuss the impact of strong absorption for thermal neutrons on data analysis and compare absorption corrections in the GSAS and MAUD Rietveld codes for texture and structural parameter refinement. Diffraction data were collected on the neutron powder diffractometer HIPPO at LANSCE from dysprosium and erbium, which are moderate to strong absorbers for thermal neutrons with absorption cross-s...

A review. Diffraction methods are a powerful tool to investigate the crystal structure of organic compounds in general and their hydrates in particular. The laboratory standard technique of single crystal X-ray diffraction gives information about the molecular conformation, packing and hydrogen bonding in the crystal structure, while powder X-ray diffraction on bulk material can trace hydration...

Neutron diffraction was employed to measure internal residual stresses at various locations along stainless steel (SS) 17-4 PH specimens additively manufactured via laser-powder bed fusion (L-PBF). Of these specimens, two were rods (diameter=8 mm, length=80 mm) built vertically upward and one a parallelepiped (8×80×9 mm3) built with its longest edge parallel to ground. One rod and the parallele...

This ISEN award supported research toward improving the energy efficiency of actuators. The focused research objective was to develop next-generation shape memory alloy (SMA) models and structures, to demonstrate this new technology in targeted near-term applications on airplanes. Two research avenues were pursued to enable development of this new technology: 1) neutron diffraction experiments ...

The work reported in this thesis concerns, not only the synthesis of mesoporous MCM-41 materials, but also their characterisation and analysis by a number of techniques. The methods used most frequently were small angle X-ray and neutron scattering. These procedures, especially when used in conjunction, are very powerful, giving much structural information in a critical size range. Other techni...