To use all functions of this page, please activate cookies in your browser.

my.chemeurope.com

With an accout for my.chemeurope.com you can always see everything at a glance – and you can configure your own website and individual newsletter.

- My watch list
- My saved searches
- My saved topics
- My newsletter

## Bragg diffractionThe W. L. Bragg explained this result by modeling the crystal as a set of discrete parallel planes separated by a constant parameter
## Additional recommended knowledge
## MechanicsAs the wave enters the crystal, some portion of it will be reflected by the first layer, while the rest will continue through to the second layer, where the process continues. By the definition of constructive interference, the separately reflected waves will remain in phase if the difference in the path length of each wave is equal to an integer multiple of the wavelength. In the figure 2 on the right, the path difference is given by , where Waves that satisfy this condition interfere constructively and result in a reflected wave of significant intensity. ## Reciprocal spaceMore elegant is the description in reciprocal space. Reciprocal lattice vectors describe the set of lattice planes as a normal vector to this plane with length and the unexperienced applicant should just remember
## Selection rules and practical x-ray crystallographyBragg's law, as stated above, can be used to obtain the lattice spacing of a particular cubic system through the following relation: Where One can derive selection rules for the Miller indices for different cubic Bravais lattices; here, selection rules for several will be given as is.
These selection rules can be used for any crystal with the given crystal structure. Selection rules for other structures can be referenced elsewhere, or derived. ## Nobel Prize for Bragg diffractionIn 1915, William Henry Bragg and William Lawrence Bragg were awarded the Nobel Prize for their contributions to crystal structure analysis. They were the first and (so far) the only father-son team to have jointly won the prize. Other father/son laureates include Niels and Aage Bohr, Manne and Kai Siegbahn, J.J. and George Thomson, Hans von Euler-Chelpin and Ulf von Euler, and Arthur and Roger Kornberg all having been awarded the prize for separate contributions. W.L. Bragg was 25 years old at the time, making him the youngest Nobel laureate to date. ## See also- Bragg's law
- Diffraction
- Distributed Bragg reflector
- Photonic crystal fiber
## References- Neil W. Ashcroft and N. David Mermin,
*Solid State Physics*(Harcourt: Orlando, 1976). - http://www.citycollegiate.com/interference_braggs.htm
- http://srs.dl.ac.uk/station/9.4/diffraction-selection-rules.htm
- http://www.physics.uoguelph.ca/~detong/phys3510_4500/xray.pdf
Categories: Condensed matter physics | Diffraction |
|||||||||||||||||||||

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Bragg_diffraction". A list of authors is available in Wikipedia. |