Written by one of the pioneers of 2D X-Ray Diffraction, this useful guide covers the fundamentals, experimental methods and applications of two-dimensional x-ray diffraction, including geometry ...convention, x-ray source and optics, two-dimensional detectors, diffraction data interpretation, and configurations for various applications, such as phase identification, texture, stress, microstructure analysis, crystallinity, thin film analysis and combinatorial screening. Experimental examples in materials research, pharmaceuticals, and forensics are also given. This presents a key resource to researchers in materials science, chemistry, physics, and pharmaceuticals, as well as graduate-level students in these areas.
Implementation of a computer program package for automated collection and processing of rotation electron diffraction (RED) data is described. The software package contains two computer programs: RED ...data collection and RED data processing. The RED data collection program controls the transmission electron microscope and the camera. Electron beam tilts at a fine step (0.05–0.20°) are combined with goniometer tilts at a coarse step (2.0–3.0°) around a common tilt axis, which allows a fine relative tilt to be achieved between the electron beam and the crystal in a large tilt range. An electron diffraction (ED) frame is collected at each combination of beam tilt and goniometer tilt. The RED data processing program processes three‐dimensional ED data generated by the RED data collection program or by other approaches. It includes shift correction of the ED frames, peak hunting for diffraction spots in individual ED frames and identification of these diffraction spots as reflections in three dimensions. Unit‐cell parameters are determined from the positions of reflections in three‐dimensional reciprocal space. All reflections are indexed, and finally a list with hkl indices and intensities is output. The data processing program also includes a visualizer to view and analyse three‐dimensional reciprocal lattices reconstructed from the ED frames. Details of the implementation are described. Data collection and data processing with the software RED are demonstrated using a calcined zeolite sample, silicalite‐1. The structure of the calcined silicalite‐1, with 72 unique atoms, could be solved from the RED data by routine direct methods.
X-ray free-electron lasers provide femtosecond-duration pulses of hard X-rays with a peak brightness approximately one billion times greater than is available at synchrotron radiation facilities. One ...motivation for the development of such X-ray sources was the proposal to obtain structures of macromolecules, macromolecular complexes, and virus particles, without the need for crystallization, through diffraction measurements of single noncrystalline objects. Initial explorations of this idea and of outrunning radiation damage with femtosecond pulses led to the development of serial crystallography and the ability to obtain high-resolution structures of small crystals without the need for cryogenic cooling. This technique allows the understanding of conformational dynamics and enzymatics and the resolution of intermediate states in reactions over timescales of 100 fs to minutes. The promise of more photons per atom recorded in a diffraction pattern than electrons per atom contributing to an electron micrograph may enable diffraction measurements of single molecules, although challenges remain.
ID15A is a newly refurbished beamline at the ESRF devoted to operando and time‐resolved diffraction and imaging, total scattering and diffraction computed tomography. The beamline is optimized for ...rapid alternation between the different techniques during a single operando experiment in order to collect complementary data on working systems. The high available energy (up to 120 keV) means that even bulky and highly absorbing systems may be studied. The beamline is equipped with optimized focusing optics and a photon‐counting CdTe pixel detector, allowing for both unprecedented data quality at high energy and for very rapid triggered experiments. A large choice of imaging detectors and ancillary probes and sample environments is also available.
ID15A is a newly refurbished beamline at the ESRF devoted to operando and time‐resolved diffraction and imaging, total scattering and diffraction computed tomography.
L sub(2)Zn sub(2) (L = HCC(Me)N(2,4,6-Me sub(3)C sub(6) H sub(2)) sub(2)) and Ph sub(2)E sub(2) (E = Se, Te) react to form LZnSePh (1) and LZnTePh (2). 1 and 2 further react with H sub(2)O and EtOH ...to form LZnOH (3) and LZnOEt (4), respectively, whereas the reaction of 2 with oxygen yielded LZnOTe(O)Ph sub(2) (5). 1, 4 and 5 were characterized by single crystal X-ray diffraction.
The Biginelli reactions of salicylaldehyde and 2‐hydroxy‐l‐naphthaldehyde with ethyl or methyl acetoacetate, ethyl benzoylacetate, and urea have been reinvestigated both in the structures of the ...reaction products and in the reaction conditions. Salicylaldehyde with ethyl and methyl acetoacetate resulted in oxygen‐bridged tricyclic tetrahydro pyrimidines, whereas with ethyl benzoylacetate afforded the only normal 3,4‐dihydropyrimidin‐2‐one. 2‐Hydroxy‐l‐naphthaldehyde with ethyl and methyl acetoacetate formed the tricyclic compounds. Steric effect is likely to be the principal determinant in governing the formation of product dichotomy. Previous controversial results as to the structure of the Biginelli products have been discussed and settled. The molecular structures of the dihydropyrimidinones and bridged tricyclic products have been fully characterized and confirmed unambiguously by single crystal X‐ray diffraction.
Zinc oxysulfide nanocrystals with zinc blende phase are synthesized through a wet-chemical method. An affirmation of the crystal structure, elemental homogeneity and phase transformation is obtained ...by X-ray diffraction and authenticated by electron micrographic studies. Theoretical observations have strongly supported the thermodynamic solubility limit for its (30%) formation. An anomalous bandgap bowing with modulation in bandgap from 3.74 eV (ZnO) to 3.93 eV (ZnS) was observed with a minimum bandgap of 2.7 eV. Tunable bandgap and a wide range of visible emission ascertain it as a potential material for optoelectronic and solar cell applications due to its large bandgap offsets.
Introduction of “Belok/XSA” beamline‐modernization is presented here with commissioning of a modern synchrotron beamline with unique capabilities for the structural analysis of single and ...polycrystalline samples. The beamline is designed to perform important tasks in modern crystallography, such as solving and refining the atomic structure using the single‐ and polycrystal method, studying the real (defective) structure, and analyzing the distribution of electron density in crystals, it is also possible to study rapidly occurring processes, for example, temperature phase transitions. Due to the speed of data accumulation and a registration over a large solid angle, the method allows to study large numbers of samples. This beamline has become extremely demanded in the chemical, biological, material science, and archaeological community in Russia.
Introduction of “Belok/XSA” beamline‐modernization is presented here with commissioning of a modern synchrotron beamline with unique capabilities for the structural analysis of single and polycrystalline samples. The beamline is designed to perform important tasks in modern crystallography and become extremely demanded in the chemical, biological, material science and archaeological community in Russia.
Solvothermal and hydrothermal synthesis, that is, synthesis taking place in a solvent at elevated temperature and pressure, is a powerful technique for the production of advanced energy materials as ...it is versatile, cheap, and environmentally friendly. However, the fundamental reaction mechanisms dictating particle formation and growth under solvothermal conditions are not well understood. In order to produce tailor-made materials with specific properties for advanced energy technologies, it is essential to obtain an improved understanding of these processes and, in this context, insitu studies are an important tool as they provide real time information on the reactions taking place. Here, we present a review of the use of powder diffraction and total scattering methods for insitu studies of synthesis taking place under solvothermal and hydrothermal conditions. The experimental setups used for insitu X-ray and neutron studies are presented, and methods of data analysis are described. Special attention is given to the methods used to extract structural information from the data, for example, Rietveld refinement, whole powder pattern modelling and pair distribution function analysis. Examples of insitu studies are presented to illustrate the types of chemical insight that can be obtained. PUBLICATION ABSTRACT
The MYTHEN single‐photon‐counting silicon microstrip detector has been developed at the Swiss Light Source for time‐resolved powder diffraction experiments. An upgraded version of the detector has ...been installed at the SLS powder diffraction station allowing the acquisition of diffraction patterns over 120° in 2θ in fractions of seconds. Thanks to the outstanding performance of the detector and to the calibration procedures developed, the quality of the data obtained is now comparable with that of traditional high‐resolution point detectors in terms of FWHM resolution and peak profile shape, with the additional advantage of fast and simultaneous acquisition of the full diffraction pattern. MYTHEN is therefore optimal for time‐resolved or dose‐critical measurements. The characteristics of the MYTHEN detector together with the calibration procedures implemented for the optimization of the data are described in detail. The refinements of two known standard powders are discussed together with a remarkable application of MYTHEN to organic compounds in relation to the problem of radiation damage.
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