Search results for "Gas electron diffraction"
showing 9 items of 9 documents
Using Electron Diffraction to Solve the Crystal Structure of a Laked Azo Pigment
2009
The structure of the ζ phase of Pigment Red 53:2 was solved using electron diffraction data. The unit cell determination appeared to be more complicated due to twinning of the crystals. A series of...
Crystal structure of disordered nanocrystalline $\alpha^{II}$-quinacridone determined by electron diffraction
2016
CrystEngComm 18(4), 529 - 535(2016). doi:10.1039/C5CE01855B
The role of electron diffraction in zeolite structure determination
2006
Because electron diffraction can sample individual microcrystals, it is clear that this single crystal method can facilitate, in at least two ways, structure determination for inorganic materials, such as zeolites, that are preferentially microcrystalline. First, in a qualitative application, three-dimensional tilts of individual small crystals, to map the reciprocal lattice, greatly facilitates unit cell and space group determination when powder diffraction indexing programs fail. If incoherent multiple scattering leads to violation of systematic absences, these absences can be restored by collection of precession diffraction patterns based on the Vincent-Midgley method [1], as demonstrate…
Elucidating structural order and disorder phenomena in mullite-type Al4B2O9 by automated electron diffraction tomography
2017
The crystal structure and disorder phenomena of Al4B2O9, an aluminum borate from the mullite-type family, were studied using automated diffraction tomography (ADT), a recently established method for collection and analysis of electron diffraction data. Al4B2O9, prepared by sol-gel approach, crystallizes in the monoclinic space group C2/m. The ab initio structure determination based on three-dimensional electron diffraction data from single ordered crystals reveals that edge-connected AlO6 octahedra expanding along the b axis constitute the backbone. The ordered structure (A) was confirmed by TEM and HAADF-STEM images. Furthermore, disordered crystals with diffuse scattering along the b axis…
Application of delta recycling to electron automated diffraction tomography data from inorganic crystalline nanovolumes
2013
δ Recycling is a simple procedure for directly extracting phase information from Patterson-type functions [Rius (2012). Acta Cryst. A68, 399-400]. This new phasing method has a clear theoretical basis and was developed with ideal single-crystal X-ray diffraction data. On the other hand, introduction of the automated diffraction tomography (ADT) technique has represented a significant advance in electron diffraction data collection [Kolb et al. (2007). Ultramicroscopy, 107, 507-513]. When combined with precession electron diffraction, it delivers quasi-kinematical intensity data even for complex inorganic compounds, so that single-crystal diffraction data of nanometric volumes are now availa…
A high pressure gas target system for the determination of absolute electron scattering cross sections
1979
A high pressure gas target system is described, which is suitable for measurements of absolute electron scattering cross sections and for high resolution electron scattering experiments at medium energies. Details of design and construction are given and special investigations are discussed with respect to straggling effects that take place in the walls and in the gases, and to changes in the gas density, due to heating by the electron beam.
Total-scattering pair-distribution function of organic material from powder electron diffraction data.
2014
AbstractThis paper shows that pair-distribution function (PDF) analyses can be carried out on organic and organometallic compounds from powder electron diffraction data. Different experimental setups are demonstrated, including selected area electron diffraction and nanodiffraction in transmission electron microscopy or nanodiffraction in scanning transmission electron microscopy modes. The methods were demonstrated on organometallic complexes (chlorinated and unchlorinated copper phthalocyanine) and on purely organic compounds (quinacridone). The PDF curves from powder electron diffraction data, called ePDF, are in good agreement with PDF curves determined from X-ray powder data demonstrat…
Structure characterization of hard materials by precession electron diffraction and automatic diffraction tomography: 6H-SiC semiconductor and Ni1+xT…
2012
Using a combination of automated diffraction tomography and precession electron diffraction techniques, quasi-kinematical electron diffraction data sets were collected from intermetallic Ni1+xTe1 embedded nanodomains and ion-thinned specimens of 6H–SiC semiconductor. Cell parameters and space groups were found automatically from the reconstructed 3D diffraction volume. The extracted intensities were used for fast ab initio structure determination by direct methods.
Electron Diffraction Reinvestigation of CdCr<sub>2</sub>Se<sub>4</sub> and ZnCr<sub>2-x</sub>V<sub>x</su…
2013
Crystal structure of two spinel single crystals CdCr2Se4 and ZnCr2-xVxSe4 have been reinvestigated using automated electron diffraction tomography method with beam precession. 3D reciprocal space have been reconstructed base on recorded tilt series. For both samples crystal structure was refined and the cubic symmetry with space group Fd-3m was confirmed. No additional electron potential has been located beside occupied atom sites.