EM Course – Elastic Scattering
Professor Rodney Herring
Reciprocal Space
This chapter has been downloaded onto the Mech 580 Electron Microscopy
website. Since the reciprocal lattice does not pertain to electron microscopy but is
necessary to help interpret your diffraction, I want you to review it by yourself. I
want you to take special attention to the Laue equations and their relation to
Bragg’s law and its relation to higher order diffraction, Laue zone lines and
acceleration voltage, and the excitation error, s.
Ewald Sphere
Diffracted beams are rods, which
intersect the surface of the Ewald
sphere. Even when tilted off exact
Bragg diffraction, there is still some
diffracted beam being created.
Ewald Sphere
Excitation Error – Deviation Parameter, S
Excitation Error – Deviation Parameter, S
Ewald Sphere, l and E
Ewald Sphere