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Diamond Anvil Cell (diamond + anvil_cell)
Selected AbstractsMacromolecular crystallography at high pressure with pneumatic diamond anvil cells handled by a six-axis robotic armJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2010Eric Girard A new pneumatic diamond anvil cell has been constructed, generating continuous pressure and temperature variations in the range 0,2.5,GPa and 293,393,K. The cell is designed mainly for high-pressure macromolecular crystallography and should facilitate pressure and temperature annealing of the sample. The analysis is reported of several diffraction data sets of tetragonal hen egg-white lysozyme crystals loaded either in the new cell or in a currently used membrane-based cell. These experiments were performed on beamline FIP-BM30A at the ESRF, Grenoble, a macromolecular crystallography beamline on a bending magnet. Cells were handled and automatically centred by a six-axis robotic arm that was used as a goniometer for data collection by the oscillation method. [source] Incorporation of a new design of backing seat and anvil in a Merrill,Bassett diamond anvil cellJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2008Stephen A. Moggach A modification to the Merrill,Bassett miniature diamond anvil cell is reported here, with the inclusion of tungsten carbide backing seats with Boehler,Almax-cut diamonds to replace the previously used beryllium seats and (typically) modified brilliant-cut anvils. This has led to the removal of troublesome beryllium powder lines from diffraction images, while maintaining the pressure range and opening angle of the original design. [source] Phonon spectroscopy at high pressure by inelastic X-ray scatteringJOURNAL OF SYNCHROTRON RADIATION, Issue 6 2009Valentina M. Giordano The current status of phonon-dispersion studies at high pressure using very high energy resolution inelastic X-ray scattering is discussed. A brief description of the instrumental apparatus is given, together with an illustration of the high-pressure facilities available at the IXS beamlines ID16 and ID28 of the ESRF. Some selected examples of recent studies on crystalline and liquid samples in a diamond anvil cell are then presented. [source] Quantitative high-pressure pair distribution function analysisJOURNAL OF SYNCHROTRON RADIATION, Issue 5 2005John B. Parise The collection of scattering data at high pressure and temperature is now relatively straightforward thanks to developments at high-brightness synchrotron radiation facilities. Reliable data from powders, that are suitable for structure determination and Rietveld refinement, are routinely collected up to about 30,GPa in either a large-volume high-pressure apparatus or diamond anvil cell. In those cases where the total elastic scattering is of interest, as it is in the case of nano-crystalline and glassy materials, technical developments, including the use of focused high-energy X-rays (>80,keV), are advantageous. Recently completed experiments on nano-crystalline materials at the 1-ID beamline at the Advanced Photon Source suggest that quantitative data, suitable for pair distribution function analysis, can be obtained. [source] X-ray emission spectroscopy with a laser-heated diamond anvil cell: a new experimental probe of the spin state of iron in the Earth's interiorJOURNAL OF SYNCHROTRON RADIATION, Issue 5 2005Jung-Fu Lin Synchrotron-based X-ray emission spectroscopy (XES) is well suited to probing the local electronic structure of 3d transition metals such as Fe and Mn in their host phases. The laser-heated diamond anvil cell technique is uniquely capable of generating ultra-high static pressures and temperatures in excess of 100,GPa and 3000,K. Here X-ray emission spectroscopy and X-ray diffraction have been interfaced with the laser-heated diamond cell for studying the electronic spin states of iron in magnesiowüstite-(Mg0.75,Fe0.25)O and its crystal structure under lower-mantle conditions. X-ray emission spectra of the ferrous iron in a single crystal of magnesiowüstite-(Mg0.75,Fe0.25)O indicate that a high-spin to low-spin transition of ferrous iron occurs at 54 to 67,GPa and 300,K and the ferrous iron remains in the high-spin state up to 47,GPa and 1300,K. This pilot study points to the unique capability of the synchrotron-based XES and X-ray diffraction techniques for addressing the issue of electronic spin transition or crossover in 3d transition metals and compounds under extreme high- P,T conditions. [source] Facilities for high-pressure research with the diamond anvil cell at GSECARSJOURNAL OF SYNCHROTRON RADIATION, Issue 5 2005Guoyin Shen An overview of facilities for high-pressure research with the diamond anvil cell (DAC) at the GeoSoilEnviroCARS (GSECARS) sector at the Advanced Photon Source (Argonne, Illinois) is presented. There are three operational experimental stations (13-ID-C, 13-ID-D and 13-BM-D) where DAC instrumentation is installed for various types of experiments at high pressure and extreme temperature conditions. A fourth station (13-BM-C) is under construction and will be operational in 2006. While most X-ray diffraction experiments have been undertaken with powder samples so far, there is a growing demand for single-crystal diffraction (SCD) at high pressure. As one of the principal components at GSECARS, SCD is currently under rapid development. Other relevant techniques have also been developed for obtaining complementary information from powder or single-crystal samples at high pressure. For example, an on-line Brillouin system is installed and operational at 13-BM-D for acoustic velocity and single-crystal elasticity determinations. In addition, various X-ray spectroscopy techniques (e.g. X-ray emission and X-ray Raman) are employed for measuring electronic and magnetic properties. Future developments are discussed with the DAC program at GSECARS. [source] XAFS study on a pressure-induced superconductor Cs3C60 under high pressureJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001Satoshi Fujiki Cs K-edge XAFS of Cs3C60 which is a pressure-induced superconductor were measured at 21 and 34 kbar by using a diamond anvil cell (DAC) in order to obtain the structural information under high pressure, and to clarify the origin of the pressure-induced superconductivity. The distances and the mean square displacements between the Cs and C atoms are consistent with those determined by X-ray powder diffraction. Consequently, the high-pressure XAFS can give the reliable structural-information on a fullerene superconductor under high pressure. We also show the procedure of the analysis of high-pressure XAFS with DAC in detail. [source] Anomalous Dynamical Charge Change Behavior of Nanocrystalline 3C-SiC upon CompressionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2004Haozhe Liu Using diamond anvil cell (DAC) technique, in situ high-pressure Raman scattering and energy-dispersive X-ray diffraction (EDXRD) experiments were used at room temperature to study 3C-SiC with an average grain size of 30 nm. In contrast to its bulk counterpart, a decrease of the Born's transverse effective charge of these nanocrystals was observed with increasing pressure from measurements of the longitudinal and transverse optical phonon modes (longitudinal optical,transverse optical) splitting. This is therefore indicative of a diminishing ionicity of nanocrystalline 3C-SiC on compression. [source] Dependence of the band-gap pressure coefficients of self-assembled InAs/GaAs quantum dots on the quantum dot sizePHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2007C. Kristukat Abstract We report on low-temperature photoluminescence experiments on self-assembled InAs/GaAs quantum dots under high hydrostatic pressure up to 8 GPa using a diamond anvil cell. The sample exhibits a multimodal size distribution of the quantum dots, which gives rise to a characteristic emission profile displaying up to nine clearly separable peaks attributed to the ground-state recombination from each quantum dot subensemble with different size. Structural analysis revealed that their size differs in entire monolayer steps. The measured pressure coefficients for each subensemble show a linear dependence on their zero-pressure emission energy ranging from 65 meV/GPa for the largest dots to 112 meV/GPa for the smallest ones. Pressure dependent strain simulations based on an atomistic valence-force field yield that the pressure coefficient of the InAs band-gap is strongly reduced when InAs is embedded in a GaAs matrix. Taking into account confinement effects within the envelope function approximation, the calculated pressure coefficients are in good agreement with the experimental findings. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Anisotropic crystal structure distortion of the monoclinic polymorph of acetaminophen at high hydrostatic pressuresACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2000E. V. Boldyreva The anisotropy of structural distortion of the monoclinic polymorph of acetaminophen induced by hydrostatic pressure up to 4.0,GPa was studied by single-crystal X-ray diffraction in a Merrill,Bassett diamond anvil cell (DAC). The space group (P21/n) and the general structural pattern remained unchanged with pressure. Despite the overall decrease in the molar volume with pressure, the structure expanded in particular crystallographic directions. One of the linear cell parameters (c) passed through a minimum as the pressure increased. The intramolecular bond lengths changed only slightly with pressure, but the changes in the dihedral and torsion angles were very large. The compressibility of the intermolecular hydrogen bonds NH,O and OH,O was measured. NH,O bonds were shown to be slightly more compressible than OH,O bonds. The anisotropy of structural distortion was analysed in detail in relation to the pressure-induced changes in the molecular conformations, to the compression of the hydrogen-bond network, and to the changes in the orientation of molecules with respect to each other in the pleated sheets in the structure. Dirichlet domains were calculated in order to analyse the relative shifts of the centroids of the hydrogen-bonded cycles and of the centroids of the benzene rings with pressure. [source] Crystal structure and stability of Tl2CO3 at high pressuresACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2010A. Grzechnik The crystal structure of dithallium carbonate, Tl2CO3 (C2/m, Z = 4), was investigated at pressures of up to 7.4,GPa using single-crystal X-ray diffraction in a diamond anvil cell. It is stable to at least 5.82,GPa. All atoms except for one of the O atoms lie on crystallographic mirror planes. At higher pressures, the material undergoes a phase transition that destroys the single crystal. [source] Bi4Ge3O12 at the onset of pressure-induced amorphizationACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2009Andrzej Grzechnik The crystal structure of tetrabismuth tris(germanate), Bi4Ge3O12 (I3d, Z = 4), is stable to at least 7.30,GPa, as demonstrated by hydrostatic single-crystal X-ray diffraction measurements in a diamond anvil cell at room temperature. The highest pressure reached in this study is close to the onset of amorphization at about 8,GPa. The Bi and Ge atoms are located at the 16c (3) and 12a () Wyckoff positions, respectively. The compression mainly affects the distorted BiO6 octahedra, while the GeO4 tetrahedra are relatively rigid. When compared with the values obtained under ambient conditions, the long Bi,O distances decrease with increasing pressure, while the short Bi,O distances do not change. [source] Tl2CO3 at 3.56 GPaACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2008A. Grzechnik The crystal structure of thallium carbonate, Tl2CO3 (C2/m, Z = 4), is stable at least up to 3.56,GPa, as demonstrated by hydrostatic single-crystal X-ray diffraction measurements in a diamond anvil cell at room temperature. Our results contradict earlier observations from the literature, which found a structural phase transition for this compound at about 2,GPa. Under atmospheric conditions, all atoms except for one O atom reside on the mirror plane in the high-pressure structure. The compression mainly affects the part of the structure where the nonbonded electron lone pairs on the Tl+ cations are located. [source] High-Pressure Behavior of Copper Carbonate: Data from MalachiteACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2009Yingxin LIU Abstract: In-situ high-pressure energy dispersive X-ray diffraction experiments of malachite have been performed using diamond anvil cell and synchrotron radiation. The highest recorded pressure is up to 17.4 GPa. The experimental results reveal that malachite experienced two phase transitions at 0.7 and 7.8 GPa, and the last one is reversible. [source] Determining Pressure with Daughter Minerals in Fluid Inclusion by Raman Spectroscopy: Sphalerite as an ExampleACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2009Yuping YANG Abstract: Raman frequency of some materials, including minerals, molecules and ions, shifts systematically with changing pressure and temperature. This property is often used as a pressure gauge in high pressure experiments with the hydrothermal diamond anvil cell (HDAC). Since the system of fluid inclusion is similar to that of HDAC, it can also be used to determine the internal pressure of fluid inclusions. Sphalerite is a common daughter mineral. In this study, the frequency shift of the 350 cm,1 peak of sphalerite has been studied from 296 to 523 K and from 0.07 to 2.00 GPa using the HDAC. The global slope of the isotherms (,V350/,p)T is 0.0048 in the studied pressure range. No significant variation of the slopes with temperature has been observed. The correlation between the frequency shift of the 350 cm,1 peak of sphalerite and pressure and temperature is constrained as P=208.33(,Vp)350+3.13T,943.75. This relationship may be used to estimate the internal pressure of the sphalerite-bearing fluid inclusions. [source] Phase Transformations During High-Pressure Torsion of Pure Zr and of a Zr-2.5%Nb Alloy,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Alexander P. Zhilyaev Zirconium at normal conditions (room temperature and atmospheric pressure) has an HCP structure with lattice parameters a,=,3.2313,Å and c,=,5.1477,Å (,-phase). During loading under hydrostatic conditions in diamond anvil cells, a transition from the , -phase to an , -phase occurs at a pressure between 2 and 6 GPa and from , to , (bcc) at 30 GPa. It has been recently reported that the , to ,,+,, transformation might be induced by HPT processing. The resulting microstructures are stable at room temperature and atmospheric pressure. This paper explores the influence of previous processing steps and of composition in the feasibility of the HPT induced , to ,,+,, transformation. It will be shown that neither previous quenching nor high temperature HPT processing prevents the transformation from occurring during subsequent room temperature HPT. The addition of elements such as Nb also seems to favor the transformation. Understanding well the potential of HPT to stabilize high-pressure phases at normal conditions might be critical, as it will open a whole new range of applications for already existing materials. [source] Macromolecular crystallography at high pressure with pneumatic diamond anvil cells handled by a six-axis robotic armJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2010Eric Girard A new pneumatic diamond anvil cell has been constructed, generating continuous pressure and temperature variations in the range 0,2.5,GPa and 293,393,K. The cell is designed mainly for high-pressure macromolecular crystallography and should facilitate pressure and temperature annealing of the sample. The analysis is reported of several diffraction data sets of tetragonal hen egg-white lysozyme crystals loaded either in the new cell or in a currently used membrane-based cell. These experiments were performed on beamline FIP-BM30A at the ESRF, Grenoble, a macromolecular crystallography beamline on a bending magnet. Cells were handled and automatically centred by a six-axis robotic arm that was used as a goniometer for data collection by the oscillation method. [source] Achievements in high-pressure science at the high-brilliance energy-dispersive X-ray absorption spectrometer of ESRF, ID24JOURNAL OF SYNCHROTRON RADIATION, Issue 6 2009Giuliana Aquilanti Although the idea of an X-ray absorption spectrometer in dispersive geometry was initially conceived for the study of transient phenomena, the instrument at the European Synchrotron Radiation facility has been increasingly exploited for studies at extreme conditions of pressure using diamond anvil cells. The main results of investigations at high pressure obtained at beamline ID24 are reviewed. These concern not only fundamental topics, such as the local and the electronic structure as well as the magnetic properties of matter, but also geological relevant questions such as the behaviour of Fe in the main components of the Earth's interior. [source] A position-sensitive ionization chamber for XAFS studies at synchrotron sourcesJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001Kazumichi Sato A position-sensitive ionization chamber has been developed with backgammon-type-segmented electrodes. This novel detector possesses a linear range of 8 mm for determining the incident position of the X-ray beam incoming. The position resolution was found to be less than 10 µm, probably close the sub-micrometer region. Owing to its high spatial resolution, the position-sensitive ionization chamber was able to commit that the gradual decrease observed in the X-ray beam intensity at a SPring-8 beamline was mainly due to the spatial variation of the X-ray beam in time. The present work also confirmed the applicability of the novel detector to the accurate monochromator adjustment for experiments using diamond anvil cells. [source] | |||||||||||||