Electron microscopy
 
Relationship between Electron Diffraction Patterns and Stereographic Projections
- Practical Electron Microscopy and Database -
- An Online Book -
Microanalysis | EM Book                                                                                   http://www.globalsino.com/EM/        

This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.
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As described on page4116, when the incident electron beam in TEM travels down a crystal from the north pole of a stereographic projection, diffractions are formed from planes whose poles intersect the equator of the sphere. For instance, for a bcc crystal as shown in Figure 3081, when the [110] direction points towards the electron gun, diffractions from the planes lie on the circumference of the [110] stereographic projection. The main relationship between the electron diffraction patterns and stereographic projections are:
        i) The angles between the vectors in the diffraction pattern and in the stereographic projection are the same. For instance, the angles that are arrowed in same colors in both cases are the same in Figures 3081 (a) and (b).
        ii) Stereographic projections provide no information about the distances between the diffraction spots.
        iii) Stereographic projections provide no information about structure factor rules. For instance, it does not suggest forbidden spots.

Relationship between Electron Diffraction Patterns and Stereographic Projections Relationship between Electron Diffraction Patterns and Stereographic Projections
(a)
(b)
Figure 3081. Relationship between diffraction pattern (a) and stereographic projection (b) of [110] zone axis for a bcc crystal.

 

 

 

 

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