ProjectionDiffraction Symmetry  Practical Electron Microscopy and Database   An Online Book  

Microanalysis  EM Book http://www.globalsino.com/EM/  


=================================================================================  
Projectiondiffraction symmetry [1] corresponds to the symmetry of the diffraction disks and diffuse intensity within diffraction disks of the zeroorder Laue zone (ZOLZ) symmetry, which excludes the HOLZ lines in the bright field disks. Figure 1601 shows the projectiondiffraction symmetry of the [0001] CBED pattern of T1 (Al_{2}CuLi) crystals. The pattern symmetry is 6mm.
Note that the projectiondiffraction symmetry can never be lower than the wholepattern symmetry since the wholepattern symmetry reflects the symmetry of the full threedimensional (3D) crystal.
[1] B. E Buxton, J.A. Eades, J.W. Steeds, and G.M. Rackham: Phil. Trans. Roy. Soc., vol. 281, A1301, pp. 17194.


=================================================================================  

