A5011238469- High-pressure geophysics and materials
- X-ray Diffraction in Crystallography
- Crystal Structures and Properties
- Geological and Geochemical Analysis
- Planetary Science and Exploration
- Iron-based superconductors research
- Diamond and Carbon-based Materials Research
- Inorganic Chemistry and Materials
- Glass properties and applications
- MXene and MAX Phase Materials
- Advanced Thermoelectric Materials and Devices
- Thermal Expansion and Ionic Conductivity
- Crystallization and Solubility Studies
- Iron oxide chemistry and applications
- Inorganic Fluorides and Related Compounds
- Rare-earth and actinide compounds
- X-ray Spectroscopy and Fluorescence Analysis
- earthquake and tectonic studies
- Thermal properties of materials
- Thermal and Kinetic Analysis
- Advanced X-ray Imaging Techniques
- Chemical Thermodynamics and Molecular Structure
- Material Dynamics and Properties
- Calcium Carbonate Crystallization and Inhibition
- Crystallography and molecular interactions
Stony Brook University
2016-2025
State University of New York
2006-2023
Brookhaven National Laboratory
2011-2021
National Synchrotron Light Source II
2011
Kiel University
2000-2010
Argonne National Laboratory
2007-2009
Geophysical Laboratory
2004-2008
Carnegie Institution for Science
2004-2008
Temple University
2007
Center for Functional Nanomaterials
2007
Despite the ubiquity of ferrihydrite in natural sediments and its importance as an industrial sorbent, nanocrystallinity this iron oxyhydroxide has hampered accurate structure determination by traditional methods that rely on long-range order. We uncovered atomic arrangement real-space modeling pair distribution function (PDF) derived from direct Fourier transformation total x-ray scattering. The PDF for synthesized with use different routes is consistent a single phase (hexagonal space...
Amorphous calcium carbonate (ACC) is an important phase involved in calcification by a wide variety of invertebrate organisms and technological interest the development functional materials. Despite widespread scientific this full characterization structure lacking. This mainly due to its metastability difficulties evaluating using conventional determination methods. Here we present new findings from application two techniques, pair distribution function analysis nuclear magnetic resonance...
Iron(III) hydroxides are abundant in near-surface natural environments and play an important role geochemical processes the fate of contaminants. The issue structure common nanophase material ferrihydrite (ferric hydroxide) is controversial has been debated literature for many years without definitive resolution. At least two types ferrihydrite, 2-line 6-line forms, conventionally recognized. It suggested that these forms possess different structures built up by mixtures distinct components....
Atoms and molecules <0.9 nm in diameter can be incorporated the cages formed by hydrogen-bonded water making up crystalline solid clathrate hydrates. For these materials crystallographic structures generally fall into 3 categories, which are 2 cubic forms a hexagonal form. A unique hydrate structure, previously known only hypothetically, has been synthesized at high pressure recovered 77 K ambient experiments. These samples contain Xe as guest atom details of this unobserved structure...
A new type of disordered substitution alloy Sb and Te at above 15.1 GPa was discovered by performing in situ high-pressure angle-dispersive X-ray diffraction experiments on antimony telluride (Sb(2)Te(3)), a topological insulator thermoelectric material, room temperature. In this alloy, Sb(2)Te(3) crystallizes into monoclinic structure with the space group C2/m, which is different from corresponding phase similar isostructural compound Bi(2)Te(3). Above 19.8 GPa, adopts body-centered-cubic...
The phase transition, amorphization, and crystallization behaviors of the topological insulator bismuth selenide (Bi2Se3) were discovered by performing in situ high-pressure angle-dispersive x-ray diffraction experiments during an increasing, decreasing, recycling pressure process. In compression process, Bi2Se3 transforms from original rhombohedral structure (phase I(A)) to a monoclinic II) at about 10.4 GPa, further body-centered tetragonal III) 24.5 GPa. When releasing ambient conditions...
Abstract We present the results of a combined study shocked labradorite from Lonar crater, India, using optical microscopy, micro‐Raman spectroscopy, nuclear magnetic resonance (NMR) high‐energy X‐ray total scattering experiments, and micro‐Fourier transform infrared (micro‐FTIR) spectroscopy. show that maskelynite shock class 2 is structurally more similar to fused glass than crystalline plagioclase. However, there are slight but significant differences—preservation original preimpact...
An experimental platform for dynamic diamond anvil cell (dDAC) research has been developed at the High Energy Density (HED) Instrument European X-ray Free Electron Laser (European XFEL). Advantage was taken of high repetition rate XFEL (up to 4.5 MHz) collect pulse-resolved MHz diffraction data from samples as they are dynamically compressed intermediate strain rates (≤10 3 s −1 ), where up 352 images can be collected a single pulse train. The set-up employs piezo-driven dDACs capable...
Abstract Chloride salt‐bearing deposits are widely distributed across the southern highlands of Mars. Because chloride salts highly water‐soluble, these may be representative last significant period stable liquid water at Martian surface. Therefore, key to understanding fate and evolution surface waters on However, little consensus exists about formation conditions deposits, their origins remain enigmatic. This is due in part because remote spectroscopic detection quantification many...
The structural behaviour of SnS under high-pressure has been investigated by angular dispersive synchrotron powder diffraction up to 38.5 GPa. A phase transition from orthorhombic α-SnS monoclinic γ-SnS was observed at 18.15 fit a Birch–Murnaghan equation-of-state gave the volume zero pressure V0 = 192.6(3) Å3, bulk modulus B0 36.6(9) GPa and derivative for 160(1) Å, 86.0(5) γ-SnS. improper ferro-elastic is first-order accompanied large discontinuity about 9.1%. can be described in terms...
Enhancement of adsorption capacity and separation radioactive Xe/Kr at room temperature above is a challenging problem. Here, we report detailed structural refinement analysis the synchrotron X-ray powder diffraction data Ni-DODBC metal organic framework with in situ Xe Kr above. Our results reveal that adsorb open sites, geometries well reproduced by DFT calculations. The measured temperature-dependent substantially larger than for Kr, indicating selectivity over consistent more negative...
The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument European Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located multipurpose vacuum chamber. Concepts pump–probe experiments DAC are described their implementation demonstrated during First User Community Assisted Commissioning experiment. heating Bi under pressure, obtained using 20...
A phenomenological model of the reconstructive transformation between NaCl and CsCl structure types is described. It consists two consecutive displacive mechanisms, coupled to tensile shear strains. These mechanisms give rise intermediate orthorhombic structures, including B16 B33 types. The shown explain consistently experimental observations in different groups binary compounds as monochalcogenides, monopnictides, monohalides. isostructural transitions found rare-earth chalcogenides are...
Abstract This paper reviews major findings of the Multidisciplinary Experimental and Modeling Impact Crater Research Network ( MEMIN ). is a consortium, funded from 2009 till 2017 by German Foundation, aimed at investigating impact cratering processes experimental modeling approaches. The vision this network has been to comprehensively quantify conducting strictly controlled campaign laboratory scale, together with multidisciplinary analytical approach. Central use powerful two‐stage...
Capture of highly volatile radioactive iodine is a promising application metal–organic frameworks (MOFs), thanks to their high porosity with flexible chemical architecture. Specifically, strong charge-transfer binding the framework enables efficient and selective uptake as well its long-term storage. As such, precise knowledge electronic structure essential for detailed modeling sorption process, which will allow rational design iodophilic MOFs in future. Here we probe at variable...
We report a pressure-induced dense tetrahedral intermediate state via Ge–O–Ge rotation formed at 3–5 GPa and the polyhedral relations in GeO2 glass up to 17.5 using situ X-ray total scattering absorption (XAFS) techniques. It was found that nearest-neighbor Ge-Ge correlations show decrease reaching minimum between 4 6 GPa, exhibit negative compression behavior 7–17.5 GPa. The Ge–Ge distance determined by XAFS shows substantial reduction, i.e., normal behavior, comparison with theoretical...
The ultrafast synthesis of ε-Fe3N1+x in a diamond-anvil cell (DAC) from Fe and N2 under pressure was observed using serial exposures an X-ray free electron laser (XFEL). When the sample at 5 GPa irradiated by pulse train separated 443 ns, estimated temperature delay time above 1400 K, confirmed situ transformation α- to γ-iron. Ultimately, reacted uniformly throughout beam path form Fe3N1.33, as deduced its established equation state (EOS). We thus demonstrate that activation energy provided...