Computer simulations for the TEM bend contour technique

1996 ◽  
Vol 54 ◽  
pp. 134-135
Author(s):  
Vladimir Yu. Kolosov ◽  
Anders R. Thölén
Keyword(s):  
Computer Simulations ◽  
Real Space ◽  
Advantages And Disadvantages ◽  
Short Overview ◽  
Diffraction Contrast ◽  
Beam Method ◽  
Convergent Beam ◽  
Contour Technique

In this paper we give a short overview of two TEM applications utilizing the extinction bend contour technique (BC) giving the advantages and disadvantages; especially we consider two areas in which the BC technique remains unique. Special attention is given to an approach including computer simulations of TEM micrographs.BC patterns are often observed in TEM studies but are rarely exploited in a serious way. However, this type of diffraction contrast was one of the first to be used for analysis of imperfections in crystalline foils, but since then only some groups have utilized the BC technique. The most extensive studies were performed by Steeds, Eades and colleagues. They were the first to demonstrate the unique possibilities of the BC method and named it real space crystallography, which developed later into the somewhat similar but more powerful convergent beam method. Maybe, due to the difficulties in analysis, BCs have seldom been used in TEM, and then mainly to visualize different imperfections and transformations.

scholarly journals Convergent beam method in X-ray diffractometry to determine single crystal cuts' orientation

2005 ◽  
Vol 61 (a1) ◽  
pp. c485-c485
Author(s):  
A. V. Lyuttsau ◽  
M. A. Kumakhov ◽  
N. S. Ibraimov ◽  
S. V. Nikitina ◽  
A. E. Bulkin ◽  
...  
Keyword(s):  
Single Crystal ◽  
X Ray ◽  
Beam Method ◽  
Convergent Beam

scholarly journals The convergent beam method for X-ray and neutron microbeam diffraction applications

2005 ◽  
Vol 61 (a1) ◽  
pp. c431-c431
Author(s):  
W. M. Gibson ◽  
C. A. MacDonald ◽  
J. X. Ho ◽  
S. M. Owens ◽  
H. Huang ◽  
...  
Keyword(s):  
X Ray ◽  
Beam Method ◽  
Convergent Beam

scholarly journals Direct visualization of orbital electron occupancy

2021 ◽  
Author(s):  
Tongtong Shang ◽  
Dongdong Xiao ◽  
Fanqi Meng ◽  
Xiaohui Rong ◽  
Xiaozhi Liu ◽  
...  
Keyword(s):  
Functional Materials ◽  
Real Space ◽  
Physical Parameters ◽  
X Ray Diffraction ◽  
The Real ◽  
Large Size ◽  
Structure Factors ◽  
Orbital Electron ◽  
Orbital Occupancy ◽  
Convergent Beam

Abstract Orbital is one of the primary physical parameters that determine materials’ properties. Currently, experimentally revealing the electron occupancies of orbitals under the control of external field remains a big challenge due to the stringent requirements for samples such as the atomically sharp surface or defect-free large-size single crystals. Here, we developed a method with the combination of quantitative convergent-beam electron diffraction and synchrotron powder X-ray diffraction, and demonstrated the visualization of the real-space orbital occupancy by choosing LiCoO2 as a prototype. Through multipole modelling of the accurately measured structure factors, we found the opposite changes of Co t2g and eg orbital occupancies under different electrochemical states which can be well-correlated with the CoO6 octahedra distortion. This robust method provides a feasible route to quantify the real-space orbital occupancy on small-sized particles, and opens up a new avenue for exploring the orbital origin of physical properties for functional materials.

Convergent-beam method in macromolecular crystallography

2002 ◽  
Vol 58 (12) ◽  
pp. 2087-2095 ◽  
Author(s):  
Joseph X. Ho ◽  
John R. Ruble ◽  
Thomas R. McInnis ◽  
Daniel C. Carter ◽  
Huapeng Huang ◽  
...  
Keyword(s):  
Macromolecular Crystallography ◽  
Beam Method ◽  
Convergent Beam

scholarly journals Teaching diffraction using computer simulations over the Internet

2001 ◽  
Vol 34 (6) ◽  
pp. 767-770 ◽  
Author(s):  
Th. Proffen ◽  
R. B. Neder ◽  
S. J. L. Billinge
Keyword(s):  
Diffraction Pattern ◽  
Computer Simulations ◽  
Materials Science ◽  
Real Space ◽  
Space Structure ◽  
Single Atom ◽  
Modulated Structures ◽  
Versatile Tool ◽  
Simulation Parameters ◽  
The Relationship

Computer simulations are a versatile tool to enhance the teaching of diffraction physics and related crystallographic topics to students of chemistry, materials science, physics and crystallography. Interactive computer simulations are presented, which have been added to a World Wide Web (WWW) based tutorial. A simple WWW interface is used to choose appropriate values for selected simulation parameters. The resulting structure and diffraction pattern are then plotted on the screen. Simulated structures range from a single atom to complex disordered or modulated structures. The simple interface requires no special computing knowledge and allows students to explore systematically the relationship between a real-space structure and the corresponding diffraction pattern. The large function set of the underlying simulation program (DISCUS) makes it easy to tailor the tutorial to a given syllabus by modifying or extending the current interactive examples.

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