Bragg's law

Bragg's law gives the condition for constructive diffraction from regularly spaced crystal planes: the path difference between reflected waves must equal an integer number of wavelengths.

Bragg diffraction: Constructive scattering of waves by successive parallel planes in a crystal. Bragg's law specifies when waves scattered by crystal planes reinforce.
X-ray crystallography: A method for determining atomic and molecular structures from X-ray diffraction by crystals. It uses Bragg conditions to relate measured diffraction angles to crystal spacings.
William Henry Bragg: An English physicist who developed X-ray spectroscopy and shared the 1915 Nobel Prize in Physics with his son. He helped formulate and experimentally apply the diffraction condition.
Laue equations: Vector equations for diffraction by a periodic lattice, requiring the scattering vector to match a reciprocal-lattice vector. They express the same diffraction conditions without treating lattice planes as reflecting mirrors.
Bragg angle: The angle between an incident beam and a diffracting crystal plane at a diffraction condition. It is the angle whose sine appears in the law.
Powder diffraction: A diffraction method that measures patterns from many randomly oriented crystallites in a powdered sample. Its rings or peaks occur at angles governed by Bragg's law.
William Lawrence Bragg: An Australian-born British physicist who formulated the relation between crystal diffraction angles and plane spacing. His 1912 insight supplied the geometric basis of the law.
Ewald sphere: A geometric construction in reciprocal space that identifies which crystal reflections satisfy diffraction conditions. It shows the broader reciprocal-space geometry underlying Bragg reflections.
Interplanar spacing: The perpendicular distance between adjacent, parallel lattice planes in a crystal. This spacing sets the path difference between waves reflected from neighboring planes.
Bragg spectrometer: An instrument that selects or measures radiation wavelengths using diffraction from a crystal. Its wavelength-angle relation is an experimental use of the law.

Linked from 36 pages