Dynamical theory of diffraction: Difference between revisions

Revision as of 11:26, 16 July 2006

Revision as of 23:54, 16 July 2006

Line 10:

* The crystal potential by itself leads to [[refraction]] and [[specular reflection]] of the waves at the interface to the crystal and delivers the [[refractive index]] off the Bragg reflection. It also corrects for refraction at the Bragg condition and combined Bragg and specular reflection in grazing incidence geometries.

* A Bragg reflection is the splitting of the dispersion surface at the border of the [[Brillouin zone]] in reciprocal space. There is a gap between the dispersion surfaces in which no travelling waves are allowed. For a non-absorbing crystal, the reflection curve shows a range of [[total reflection]], the so-called [[Darwin plateau]]. Regarding the quantum mechanical [[energy]] of the system, this leads to the [[band- gap]] structure which is commonly well known for electrons.

* Upon Laue diffraction, intensity is shuffled from the forward diffracted beam into the Bragg diffracted beam until extinction. The diffracted beam itself fulfills the Bragg condition and shuffles intensity back into the primary direction. This round-trip period is called the ''[[Pendellösung]]'' period.