The three-dimensional structure of A-amylose crystals, as a model the crystal domains A-starch granules, was revised using synchrotron radiation microdiffraction data collected from individual micron-sized single crystals. resulting sets allowed determination with conventional X-ray techniques normally used for small molecules and not polymers. Whereas gross features this improved do differ extensively previous determination, high resolution diffraction diagrams, which is unusual crystalline...

A pressure-induced phase transition from the fcc to a hexagonal close-packed (hcp) structure was found in NiCoCrFe solid solution alloy starting at 13.5 GPa. The is very sluggish and did not complete ∼40 hcp quenchable ambient pressure. Only small amount (<5%) of isostructural NiCoCr ternary up pressure 45 GPa no obvious NiCoCrFePd system till 74 Ab initio Gibbs free energy calculations indicated differences between phases for three alloys are small, but they sensitive temperature....

A new metal organic framework (MOF)-type aluminum pyromellitate or Al4(OH)8[C10O8H2]·4.8−5H2O (called MIL-120) has been hydrothermally synthesized at 210 °C for 24 h. Its structure was analyzed by single-crystal microdiffraction using the synchrotron radiation beamline ID13 station (ESRF, Grenoble). It consists of infinite chains centers in octahedral coordination connected to each other through linker. The structural feature is existence AlO2(OH)4 octahedra linked via a common edge...

A new metal−organic framework (MOF)-type aluminum pyromellitate (MIL-118) has been hydrothermally synthesized in water at 210 °C for 24 h. The crystal structure of the as-synthesized phase (Al2(OH)2(H2O)2[C10O8H2] or MIL-118A) solved from single-crystal analysis using synchrotron radiation with a specific microdiffraction setup ESRF ID13 beamline. It consists infinite chains trans-connected aluminum-centered octahedra linked to each other through ligand. organic linker is not fully...

Controlling the solid-state polymerization of organic molecules to form crystalline materials remains a challenge for synthetic chemist. In an effort control reaction pathways through topochemistry, we have compressed 1:1 naphthalene–octafluoronaphthalene cocrystal, C10H8·C10F8. This starting material displays unique structure wherein are aligned in nearly sandwich-like π–π stacking arrangement because inverse polarities naphthalene and its perfluoronated derivative. use fluorine as...

The monochromator and focusing mirrors of the 16-BM-D beamline, which is dedicated to high-pressure research with micro-X-ray diffraction (micro-XRD) X-ray absorption near edge structure (XANES) (6-45 keV) spectroscopy, have been recently upgraded. Monochromatic X-rays are selected by a Si (111) double-crystal operated in an artificial channel-cut mode focused 5 μm × (FWHM) table-top Kirkpatrick-Baez type located sample stage. typical flux ∼5 10(8) photons/s at 30 keV. instrumental...

We have explored the high-pressure structural, vibrational, electronic, and magnetic behavior of multiferroic $\mathrm{CoC}{\mathrm{r}}_{2}{\mathrm{O}}_{4}$ spinel up to 30 GPa by means x-ray diffraction, Raman spectroscopy, density functional theory calculations. Our investigations revealed a reversible tetragonal distortion starting cubic structure above 16 GPa. suggest that structural modification is mainly driven effects induced under pressure. The results obtained are compared with...

Seifertite SiO2 likely exists as a minor phase near the core–mantle boundary. By simulating pressure and temperature conditions boundary, seifertite was synthesized in coarse-grained, polycrystalline sample coexisting with (Mg,Fe)SiO3 post-perovskite (pPv) at 129 GPa 2500 K. Here we report first situ single-crystal structure determination refinement of high after quench from laser heating. We improved data coverage diamond-anvil cell (DAC) by merging six selected grains that had different...

Significance Pressure-induced metallization of solid hydrogen is a problem certain prominence in high-pressure physics. However, it extremely challenging to be achieved experimentally. It was proposed that “chemical precompression” (introducing impurity atoms or molecules into hydrogen) may facilitate under pressure. In this paper, we selected Ar(H 2 ) as model system and explored the intermolecular interactions H presence weakly bound (Ar). Combining our experimental data theoretical...

Τhe magnetoelectric $\mathrm{ZnC}{\mathrm{r}}_{2}\mathrm{S}{\mathrm{e}}_{4}$ spinel, with space group $Fd\overline{3}m$, undergoes a reversible first-order structural transition initiating at 17 GPa, as revealed by our high-pressure x-ray diffraction studies room temperature. We tentatively assign the modification to an $A\mathrm{M}{\mathrm{o}}_{2}{\mathrm{S}}_{4}$-type phase, distorted variant of monoclinic $\mathrm{C}{\mathrm{r}}_{3}{\mathrm{S}}_{4}$ structure. Furthermore, Raman...

Crystalline diiodoacetylene (C2I2) was synthesized and then studied under high-pressure conditions using synchrotron X-ray diffraction, Raman/infrared spectroscopies, first-principles calculations. At ∼0.3 GPa, the starting tetragonal (P42/n) phase, which is stabilized by donor–acceptor interactions, transforms into a new orthorhombic structure (Cmca) that more densely packed analogous to low-temperature phase of acetylene. Above approximately 4 compressed C2I2 molecules in Cmca begin...

A layered aluminium carboxylate containing the 4,4′-azobenzenedicarboxylate anion (MIL-129) has been hydrothermally synthesized (210 °C, 24 h). Its crystal structure was determined by means of microdiffraction technique using synchrotron radiation. It consists infinite trans-connected chains aluminium-centered octahedra, linked to each other through organic molecules, in order generate sheets, double stacking species. The cohesion is ensured close packing due π–π interactions between...

The 1 : acetylene–benzene cocrystal, C₂H₂·C₆H₆, was synthesized under pressure in a diamond anvil cell (DAC) and its evolution studied with single-crystal X-ray diffraction Raman spectroscopy.

An approach using polychromatic x-ray Laue diffraction is described for studying pressure induced microstructural changes of materials under pressure. The advantages this with respect to application monochromatic and other techniques are discussed. Experiments demonstrate the applications method have been performed on α → β phase transition in Si at high pressures a diamond anvil cell. We present characterization microstructures across α–β transition, such as morphology both parent product...

Recent band structure calculations have suggested the potential for tuning in chiral semiconductor Ag3AuTe2 to zero upon application of negative strain. In this study, we report on synthesis polycrystalline and investigate its transport optical properties mechanical compressibility. Transport measurements reveal semiconducting behavior with high resistivity an activation energy Ea 0.2 eV. The bandgap determined by diffuse reflectance is about three times wider than experimental Ea. Despite...

ADVERTISEMENT RETURN TO ISSUEPREVNoteA-Amylose Single Crystals: Unit Cell Refinement from Synchrotron Radiation Microdiffraction DataD. Popov, M. Burghammer, A. Buléon, N. Montesanti, J. L. Putaux, and C. RiekelView Author Information European Facility, BP 220, F-38043 Grenoble Cedex, France; INRA, Unité Biopolymères, 71627 rue de la Géraudière, 71627, 44316 Nantes Cedex 3, Centre Recherches sur les Macromolécules Végétales, ICMG-CNRS, 53, F-38041 9, France Cite this: Macromolecules 2006,...

We report an in situ Raman study of KClO4 irradiated with x-rays a diamond anvil cell. Decomposition via + hv → KCl 2O2 was monitored the O2 vibron at 2 GPa, 6 and 9 GPa. For all pressures, grew intensity then diminished after successive irradiation suggesting that diffusing away from region. Surprisingly, diffusion rate accelerated pressure increase, indicating nonhydrostatic gradient likely driving molecular oxygen. At bifurcated exists as two forms: interstitial bulk solid. This method...

Rare-earth free permanent magnet MnBi (NiAs-type crystal structure) displays strong uniaxial magnetic anisotropy above its $\ensuremath{\sim}90$ K spin reorientation transition (SRT). X-ray circular dichroism (XMCD) measurements at the Mn and Bi ${\mathrm{L}}_{2,3}$ edges show induced magnetism in Bi, which is strongly coupled to of Mn. Temperature- pressure-dependent XMCD results reveal that hydrostatic pressure mimics effect temperature, driving a from in-plane anisotropy. The temperature...

To determine the level of development science, it is necessary to start with a particular stage in society. At present, purpose building materials science create composites, which ensure safety buildings and structures, including their protection against certain natural man-made impacts. A new construction envisages technology for creating composites comfortable person. implement this, paradigm designing synthesizing raw material base needed. The optimization "human-material-habitat" system...