Diffraction

Diffraction vector: difference between the wave vector of the scattered wave and the incident wave

Structure factor: interferences of waves scattered by the atoms inside the cell

Shape factor: interferences of waves scattered by the different cells

When the diffraction vector K stays on the same direction, this means that wave vectors of the the incidence and scattered waves move symetrically

On a single crystal, there is diffraction when the diffraction vector K meet the reciprocal lattice

On a powder, there is diffraction when the diffraction vector K meet the sphere formed by the node of all the reciprocal lattice

When the incidence wave vector is fixed, the possible diffraction vectors form a sphere called the Ewald sphere or reflection sphere

The intersection of the sphere of the nodes of the reciprocal lattice and the Ewald sphere show that the wave vector of the diffused wave whene there is diffraction form a cone

Limiting sphere: obtained by the rotation around the origin of the refelction(Ewald) sphere

Rotation of the Ewald sphere and Bragg-Brentano geometry (direction of the diffraction vector fixed)

Drawing explaining the principle behind two-slit diffraction.

Bragg diffraction from a cubic lattice

Illustration of two-slit diffraction, based on a sketch by Thomas Young

Spectrum from a mercury streetlight diffracted through a compact disc.

Diffraction pattern seen in a spiderweb

Diffraction angles of a red laser at 600 lines per mm

Diffraction waves at ocean surface