نتایج جستجو برای: ray diffraction

تعداد نتایج: 327749  

2015
Thomas D. Murray Artem Y. Lyubimov Craig M. Ogata Huy Vo Monarin Uervirojnangkoorn Axel T. Brunger James M. Berger

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common...

Journal: :Acta Crystallographica Section A Foundations of Crystallography 2010

Journal: :Physical review letters 2009
S L Johnson E Vorobeva P Beaud C J Milne G Ingold

We present a complete characterization of the unit cell dynamics of a laser-excited tellurium crystal using femtosecond x-ray diffraction. The analysis offers a quantitative measure of the unit cell dynamics without making any assumptions on the symmetry of the excited-state motion. The results show a large-amplitude coherently excited A(1) mode quantitatively consistent with the predictions of...

Journal: :Optics express 2012
J Gulden O M Yefanov A P Mancuso R Dronyak A Singer V Bernátová A Burkhardt O Polozhentsev A Soldatov M Sprung I A Vartanyants

A coherent x-ray diffraction experiment was performed on an isolated colloidal crystal grain at the coherence beamline P10 at PETRA III. Using azimuthal rotation scans the three-dimensional (3D) scattered intensity from the sample in the far-field was measured. It includes several Bragg peaks as well as the coherent interference around these peaks. The analysis of the scattered intensity reveal...

Journal: :Physical review letters 2002
I K Robinson P A Bennett F J Himpsel

The structure of the Au/Si(557) surface is determined from three-dimensional x-ray diffraction measurements, which directly mandate a single Au atom per unit cell. We use a "heavy atom" method in which the Au atom images the rest of the structure. Au is found to substitute for a row of first-layer Si atoms in the middle of the terrace, which then reconstructs by step rebonding and adatoms. The ...

Journal: :Physical review letters 2008
C G Schroer P Boye J M Feldkamp J Patommel A Schropp A Schwab S Stephan M Burghammer S Schöder C Riekel

Coherent x-ray diffraction imaging is an x-ray microscopy technique with the potential of reaching spatial resolutions well beyond the diffraction limits of x-ray microscopes based on optics. However, the available coherent dose at modern x-ray sources is limited, setting practical bounds on the spatial resolution of the technique. By focusing the available coherent flux onto the sample, the sp...

2014
Philip J. Withers

We consider whether it is possible to recover the three dimensional strain field tomographically from neutron and X-ray diffraction data for polycrystalline materials. We show that the distribution of strain transverse to a ray cannot be deduced from one diffraction pattern accumulated along that path, but that a certain moment of that data corresponds to the transverse ray transform of the str...

Journal: :Physical review letters 2009
Emil Wolf

We present a solution to a long-standing basic problem encountered in the theory of structure determination of crystalline media from x-ray diffraction experiments; namely, the problem of determining phases of the diffracted beams.

2016
Sanjay Singh S W D'Souza J Nayak E Suard L Chapon A Senyshyn V Petricek Y Skourski M Nicklas C Felser S Chadov

Antiferromagnetic spintronics is a rapidly growing field, which actively introduces new principles of magnetic storage. Despite that, most applications have been suggested for collinear antiferromagnets. In this study, we consider an alternative mechanism based on long-range helical order, which allows for direct manipulation of the helicity vector. As the helicity of long-range homogeneous spi...

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