Comparative analysis of continuous rotation electron diffraction (cRED) data using Bloch-wave simulations.

2021 ◽  
Author(s):  
Anton Cleverley
Keyword(s):  
Comparative Analysis ◽  
Electron Diffraction ◽  
Bloch Wave ◽  
Continuous Rotation

Convergent-beam electron diffraction at high spatial resolution

1992 ◽  
Vol 50 (2) ◽  
pp. 1152-1153 ◽  
Author(s):  
J W Steeds
Keyword(s):  
Electron Diffraction ◽  
High Temperature Superconductors ◽  
Bloch Wave ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Energy Filtering ◽  
Small Probe ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Convergent Beam

That the techniques of convergent beam electron diffraction (CBED) are now widely practised is evident, both from the way in which they feature in the sale of new transmission electron microscopes (TEMs) and from the frequency with which the results appear in the literature: new phases of high temperature superconductors is a case in point. The arrival of a new generation of TEMs operating with coherent sources at 200-300kV opens up a number of new possibilities.First, there is the possibility of quantitative work of very high accuracy. The small probe will essentially eliminate thickness or orientation averaging and this, together with efficient energy filtering by a doubly-dispersive electron energy loss spectrometer, will yield results of unsurpassed quality. The Bloch wave formulation of electron diffraction has proved itself an effective and efficient method of interpreting the data. The treatment of absorption in these calculations has recently been improved with the result that <100> HOLZ polarity determinations can now be performed on III-V and II-VI semiconductors.

Comparative analysis of high energy electron diffraction patterns from LB films of Cd- and Pb-stearates

1996 ◽  
Vol 284-285 ◽  
pp. 208-210 ◽  
Author(s):  
V. Klechkovskaya ◽  
M. Anderle ◽  
R. Antolini ◽  
R. Canteri ◽  
L. Feigin ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Electron Diffraction ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Lb Films ◽  
Diffraction Patterns

Computer studies on reflection high-energy electron diffraction from the growing surface of Ge(001)

2013 ◽  
Vol 46 (4) ◽  
pp. 1024-1030 ◽  
Author(s):  
Zbigniew Mitura
Keyword(s):  
Experimental Data ◽  
Electron Diffraction ◽  
High Energy ◽  
Bloch Wave ◽  
Energy Electron ◽  
High Energy Electron ◽  
Homoepitaxial Growth ◽  
Scattering Potential ◽  
Computer Studies ◽  
Quantitative Explanation

The results of calculations of reflection high-energy electron diffraction intensities, measured at different stages of the homoepitaxial growth of Ge(001), are described. A two-dimensional Bloch wave approach was used in calculations of the Schrödinger equation with a one-dimensional potential. The proportional model was used for partially filled layers,i.e.the scattering potential was taken to be proportional to the coverage and the potential of the fully filled layer. Using such an approach, it was shown that it is possible to obtain valuable information for the analysis of experimental data. The results of these calculations were compared with data for off-symmetry azimuths from the literature, and satisfactory agreement between the theoretical and experimental data was found. Also assessed was whether developing more advanced models (i.e.going beyond the proportional model), to make a more detailed account of the diffuse scattering, might be important in achieving a fully quantitative explanation of the experimental data.

scholarly journals On the Completeness of Three-Dimensional Electron Diffraction Data for Structural Analysis of Metal-Organic Frameworks

2021 ◽  
Author(s):  
Meng Ge ◽  
Taimin Yang ◽  
Yanzhi Wang ◽  
Francesco Carraro ◽  
Weibin Liang ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Electron Diffraction ◽  
Structural Model ◽  
Metal Organic Frameworks ◽  
Three Dimensional ◽  
Electron Diffraction Data ◽  
Dimensional Electron ◽  
Data Completeness ◽  
Continuous Rotation ◽  
Metal Organic

<p>Three-dimensional electron diffraction (3DED) has been proven as an effective and accurate method for structure determination of nano-sized crystals. In the past decade, the crystal structures of various new complex metal-organic frameworks (MOFs) have been revealed by 3DED, which has been the key to understand their properties. However, due to the design of transmission electron microscopes (TEMs), one drawback of 3DED experiments is the limited tilt range of goniometer, which often leads to incomplete 3DED data, particularly when the crystal symmetry is low. This drawback can be overcome by high throughput data collection using continuous rotation electron diffraction (cRED), where data from a large number of crystals can be collected and merged. Here, we investigate the effects of improving completeness on structural analysis of MOFs. We use ZIF-EC1, a zeolitic imidazolate framework (ZIF), as an example. ZIF-EC1 crystallizes in a monoclinic system with a plate-like morphology. cRED data of ZIF-EC1 with different completeness and resolution were analyzed. The data completeness increased to 92.0% by merging ten datasets. Although the structures could be solved from individual datasets with a completeness as low as 44.5% and refined to a high precession (better than 0.04 Å), we demonstrate that a high data completeness could improve the structural model, especially on the electrostatic potential map. We further discuss the strategy adopted during data merging. We also show that ZIF-EC1 doped with cobalt can act as an efficient electrocatalyst for oxygen reduction reaction. </p>

scholarly journals Automated serial rotation electron diffraction combined with cluster analysis: an efficient multi-crystal workflow for structure determination

IUCrJ ◽  
2019 ◽  
Vol 6 (5) ◽  
pp. 854-867 ◽  
Author(s):  
Bin Wang ◽  
Xiaodong Zou ◽  
Stef Smeets
Keyword(s):  
Cluster Analysis ◽  
Electron Diffraction ◽  
Data Collection ◽  
Structure Analysis ◽  
Structure Determination ◽  
Hierarchical Cluster ◽  
Electron Diffraction Data ◽  
Data Sets ◽  
Analysis Tool ◽  
Continuous Rotation

Serial rotation electron diffraction (SerialRED) has been developed as a fully automated technique for three-dimensional electron diffraction data collection that can run autonomously without human intervention. It builds on the previously established serial electron diffraction technique, in which submicrometre-sized crystals are detected using image processing algorithms. Continuous rotation electron diffraction (cRED) data are collected on each crystal while dynamically tracking the movement of the crystal during rotation using defocused diffraction patterns and applying a set of deflector changes. A typical data collection screens up to 500 crystals per hour, and cRED data are collected from suitable crystals. A data processing pipeline is developed to process the SerialRED data sets. Hierarchical cluster analysis is implemented to group and identify the different phases present in the sample and to find the best matching data sets to be merged for subsequent structure analysis. This method has been successfully applied to a series of zeolites and a beam-sensitive metal–organic framework sample to study its capability for structure determination and refinement. Two multi-phase samples were tested to show that the individual crystal phases can be identified and their structures determined. The results show that refined structures obtained using automatically collected SerialRED data are indistinguishable from those collected manually using the cRED technique. At the same time, SerialRED has lower requirements of expertise in transmission electron microscopy and is less labor intensive, making it a promising high-throughput crystal screening and structure analysis tool.

Why the Bloch Wave Solution for Reflection Fails on the Au(110) Surface

1990 ◽  
Vol 48 (2) ◽  
pp. 372-373
Author(s):  
YIQUN MA
Keyword(s):  
Electron Diffraction ◽  
Wave Solution ◽  
Incident Angle ◽  
High Energy ◽  
Bloch Wave ◽  
Energy Electron ◽  
Wave Method ◽  
High Energy Electron ◽  
Real Potential ◽  
Electron Reflection

The Bloch wave method has been widely used for interpreting reflection high energy electron diffraction (RHEED) patterns and the consistency between the theory and high energy electron reflection (HEER) experiments has been claimed by different authors. The recent rigorous investigation on the consistency between the Bloch wave method and the multislice approach due to Cowley and Moodie in the reflection case for Au(001) surface has also provided a clear theoretical proof for the validity of the Bloch wave method in reflection case. However, a severe deviation of the Bloch wave solution for the Au(110) surface in the reflection case from the stabilized solution of its multislicing via the multislice iteration has recently revealed by the BMCR method (Bloch wave + Multislice Combined for Reflection).Fig.1 shows the results calculated for the Au(110) surface using the BMCR method. The incident angle is 30mRad and the absorption is included by taking the imaginary potential as 10% of the real potential in both the Bloch wave and multislice calculation.

Sign in / Sign up

Export Citation Format

Share Document