Bragg diffraction - How to make sense of it ?

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    Bragg Diffraction
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SUMMARY

The discussion centers on understanding Bragg diffraction without oversimplified explanations, particularly the common notion of "Reflection of X Rays by parallel planes." Participants suggest starting with the Laue equations or the quantum mechanical Bloch theorem to derive the Bragg equation. The Bragg equation is recognized for its simplicity and accuracy, especially in electron diffraction work. Additionally, resources such as P. P. Ewald's article provide a comprehensive overview of diffraction mechanisms without heavy mathematical formalism.

PREREQUISITES
  • Understanding of Bragg's Law and its applications in X-ray diffraction.
  • Familiarity with Laue equations and their derivation.
  • Basic knowledge of quantum mechanics, particularly Bloch theorem.
  • Concepts of atomic scattering and elastic scattering from crystals.
NEXT STEPS
  • Study the derivation of Bragg's Law from Laue equations.
  • Explore the Bloch theorem in quantum mechanics.
  • Read P. P. Ewald's article on X-ray diffraction for a non-mathematical overview.
  • Investigate the principles of atomic scattering and its role in diffraction patterns.
USEFUL FOR

Researchers, physicists, and students in materials science or crystallography seeking to deepen their understanding of Bragg diffraction and its underlying physical mechanisms.

svrphy
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Bragg diffraction - How to make sense of it ??

Is there a way to make sense of Diffraction of X Rays without taking recourse to oversimplified concepts like "Reflection of X Rays by parallel planes" which is generally the explanation in most basic physics books. It's been a couple years since I first studied it and i continue to get confused by assertions like reflecting of Photons by atoms. Online sources are also full of it :

http://www-outreach.phy.cam.ac.uk/camphy/xraydiffraction/xraydiffraction7_1.htm
OR
http://chemwiki.ucdavis.edu/Analytical_Chemistry/Instrumental_Analysis/Diffraction/Bragg's_Law
 
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You can start with the Laue equations, which are derived from interference principles used in gratings, and derive the Bragg equation from them: http://www.phys.utk.edu/courses/Fall%202009/physics671/chapter1c.pdf

Or you can start with the fully quantum mechanical Bloch theorem and derive the Bragg equation:
http://www.uni-tuebingen.de/meso/ssscript/blochelectrons.pdf

But the Bragg equation is very simple, and very accurate, so I have used it extensively in my electron diffraction work.
 
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I get that. But, is there a way to explain things without relying on mathematical formalism. I mean a general discussion on the physical mechanism.
 
Read chapter two of this dissertation: http://hdl.handle.net/2027.42/63758

It starts with crystal theory, atomic scattering, and elastic scattering from crystals ... in short, a derivation of diffraction patterns starting from scratch.
 
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M Quack said:
This article by P. P. Ewald, one of the founding fathers of x-ray diffraction, give an excellent overview without excessive math.

http://rmp.aps.org/abstract/RMP/v37/i1/p46_1

Thanks for the link. If you have access, could you pls give me the pdf ?
 

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