A5038444727- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Crystallography and molecular interactions
- High-pressure geophysics and materials
- Solid-state spectroscopy and crystallography
- Crystal Structures and Properties
- Nuclear Physics and Applications
- Energetic Materials and Combustion
- Chemical Thermodynamics and Molecular Structure
- Inorganic Fluorides and Related Compounds
- Ferroelectric and Piezoelectric Materials
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Rare-earth and actinide compounds
- Multiferroics and related materials
- Cardiac Valve Diseases and Treatments
- Nuclear materials and radiation effects
- Cardiac and Coronary Surgery Techniques
- Thermal Expansion and Ionic Conductivity
- Advanced Chemical Physics Studies
- Iron-based superconductors research
- Aortic Disease and Treatment Approaches
- Veterinary Orthopedics and Neurology
- Cardiac, Anesthesia and Surgical Outcomes
- Nonlinear Optical Materials Research
Rutherford Appleton Laboratory
2011-2024
University of Glasgow
2009-2023
Research Complex at Harwell
2019
Science and Technology Facilities Council
2011-2015
Didcot Community Hospital
2015
Université Côte d'Azur
2014
University of Edinburgh
1995-2013
University of South Florida
2008-2012
University of Strathclyde
2009
University of Southampton
2009
We show that the Mott transition in orbitally degenerate systems can, and often does, proceed not standard ``Mott insulator---weakly correlated metal'' sequence, but via a novel intermediate phase with charge (rather than orbital) ordering. Lifting an orbital degeneracy this way can be viewed as alternative to Jahn-Teller distortion. This may occur crossover between localized itinerant regimes, if Hund's rule coupling overcomes on site Coulomb repulsion. both by calculations experiment...
The cementite phase of Fe 3 C has been studied by high-resolution neutron powder diffraction at 4.2 K and 20 intervals between 600 K. crystal structure remains orthorhombic ( Pnma ) throughout, with the fractional coordinates all atoms varying only slightly (the magnetic ferromagnetic could not be determined). transition, T c ≃ 480 K, greatly affects thermal expansion coefficient material. average volumetric above was found to 4.1 (1) × 10 −5 −1 ; below it is considerably lower (< 1.8...
The PEARL instrument at ISIS has been designed for, and dedicated to, in situ studies of materials high pressure, using the Paris–Edinburgh press. In recent years, upgrades to have led improvements data quality range achievable pressures temperatures; currently 0.5–28 GPa 80–1400 K. This paper describes technical characteristics instrument, its current capabilities, gives a brief overview science that performed, representative examples.
Using a combination of X-ray single crystal and neutron powder diffraction, the structure high-pressure γ-form RDX has been determined at 5.2 GPa shows that molecules adopt different conformations compared to conformation found in ambient-pressure α-form.
The crystal structure of the highly metastable beta-form RDX shows that molecules adopt different conformations compared to alpha-form and that, contrary previous reports, obtained at ambient pressure is not same form as elevated temperatures pressures.
Abstract While new biomaterials for regenerative therapies are being reported in the literature, clinical translation is slow. Some existing approaches rely on high doses of growth factors, such as bone morphogenetic protein‐2 (BMP‐2) regeneration, which can cause serious side effects. An ultralow‐dose factor technology described yielding bioactivity based a simple polymer, poly(ethyl acrylate) (PEA), and mechanisms to drive stem cell differentiation regeneration critical‐sized murine defect...
This work reports the hydrostatic compression of perdeuterated α-form FOX-7 using neutron powder diffraction to follow structural changes up 4.58 GPa at room temperature. The equation state for over range 0–4.14 has been determined, and a phase transition was observed pressure 3.63–4.24 GPa. On basis dispersion-corrected density functional theory (DFT-D) calculations performed on γ-form pressures, high-pressure form in experiments can unambiguously be identified as being different from...
Mortality in burned patients is related to the size and depth of burn. However, effects subsequent physiologic subsystem failure on mortality have not been determined. One hundred sixty-eight with second- third-degree burns involving 40% or greater body surface area were analyzed determine relationship mortality. Cardiovascular was defined as need for catecholamines blood pressure support, pulmonary requirement mechanical ventilatory assistance, renal hemodialysis, immunologic presence...
We have applied a combination of spectroscopic and diffraction methods to study the adduct formed between squaric acid bypridine, which has been postulated exhibit proton transfer associated with single-crystal phase transition at ca. 450 K. A X-ray very-high flux powder neutron data confirmed that does from base in high-temperature form. Powder measurements demonstrated was reversible but significant kinetic energy barrier must be overcome revert original structure. Computational modeling...
Not so simple: It is normally assumed that deuteration has only a minor effect on the stabilities of crystal structures. This assumption wrong for pyridine. A low-temperature polymorph exists [D5]pyridine, but not [H5]pyridine, which adds further twist to already unusual structural chemistry one simplest and most familiar laboratory chemicals.
The high-pressure, high-temperature ε-form of the widely used explosive RDX has been structurally characterised using a combination diffraction techniques, and sample this form successfully recovered to ambient pressure.
L-Alanine crystallises as a zwitterion in space group P212121 at ambient pressure. The strongest intermolecular interactions are three N–H⋯O hydrogen bonds. H-bonds link the molecules into puckered layers ac plane, which then stacked along b axis. PIXEL calculations indicate that H-bond mediated energies within 118 and 145 kJ mol−1, while stacking considerably weaker (31 mol−1). Neutron powder diffraction data on L-alanine-d7 to 9.87 GPa show effects of pressure most prominent a, direction...
The crystal structure of the high-pressure ζ-form high explosive CL-20 has been determined using a combination X-ray single and powder diffraction techniques.
Full structural studies of condensed media under high pressure by neutron powder diffraction have been limited in practice to 2–3 GPa for several decades. This range is general too small allow a precise determination the dependence atomic coordinates. As consequence, almost no direct measurements exist, example, bond lengths H2 and planetary ices. In this letter, technique presented which makes it possible pressurize samples 35 mm3 volume up 30 collect patterns few hours time-of-flight...
High-pressure neutron diffraction studies of boron carbide, ${\mathrm{B}}_{4}$C, to 11 GPa show that the icosahedral structural units are 23(4)% more compressible than structure between them. This inverted-molecular compression is in accordance with qualitative predictions based on models bonding, but had not previously been observed directly. The results effect electrical resistivity be complex present, semiquantitative suggest.
The hydrostatic compression of L-serine- d 7 has been studied to 8.1 GPa by neutron powder diffraction. Over the course this pressure range compound undergoes two phase transitions, first between 4.6 and 5.2 GPa, yielding L-serine-II, second 7.3 L-serine-III. All three polymorphs are orthorhombic, P 2 1 , feature chains serine molecules connected via head-to-tail ND...O hydrogen bonds formed ammonium carboxylate groups. linked into a ribbon set bonds. hydroxyl moieties distributed along...