Bragg diffraction - How to make sense of it ?

In summary, a good way to make sense of Diffraction of X Rays without resorting to oversimplified concepts is to start with crystal theory, atomic scattering, and elastic scattering from crystals, and derive the Bragg equation from them.
  • #1
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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  • #2
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 [Broken]

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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  • #3
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.
 
  • #4
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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  • #6
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 ?
 

1. What is Bragg diffraction and how does it work?

Bragg diffraction is a phenomenon in which X-rays or other types of electromagnetic radiation are diffracted by the atoms in a crystal lattice. This occurs when the wavelength of the radiation is on the same order of magnitude as the spacing between the atoms in the crystal. The diffraction pattern that is produced can be analyzed to determine the structure of the crystal.

2. How is Bragg diffraction used in scientific research?

Bragg diffraction is a powerful tool in the field of crystallography, which is the study of crystal structures. By analyzing the diffraction pattern produced by X-rays or other radiation, scientists can determine the arrangement of atoms in a crystal and gain insights into its properties and behavior. This information is crucial in fields such as materials science, chemistry, and biology.

3. What are the key factors that influence Bragg diffraction?

The main factors that affect Bragg diffraction are the wavelength of the radiation, the angle of incidence, and the spacing between the atoms in the crystal lattice. The wavelength and angle of incidence determine the angle at which the diffraction peaks will occur, while the spacing between atoms affects the intensity of the peaks. Other factors, such as crystal imperfections and the orientation of the crystal, can also influence the diffraction pattern.

4. How can we make sense of the diffraction pattern produced by Bragg diffraction?

To make sense of the diffraction pattern, scientists use mathematical models and calculations to interpret the data. By analyzing the position and intensity of the diffraction peaks, they can determine the spacing between atoms in the crystal and the orientation of the crystal lattice. Computer software is often used to help with this analysis, making the process faster and more accurate.

5. What are the practical applications of Bragg diffraction outside of scientific research?

Bragg diffraction has many practical applications in various fields. For example, it is used in X-ray crystallography to determine the structure of proteins and other biomolecules, which is crucial for drug discovery and development. In materials science, Bragg diffraction is used to study the properties of materials and to develop new materials with specific characteristics. It is also used in non-destructive testing techniques, such as X-ray diffraction imaging, to analyze the structure of objects without damaging them.

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