Question

Diffraction is the result of radiation being scattered by a regular array of scattering centers whose spacing is about the same as the wavelength of the radiation. For example, paraliel scratch lines spaced repeatedly about 1 um apart cause diffraction of visible light and we can think of crystal structures as being diffraction gratings on a subnanometer scale. The first elght planes that give x-ray diffraction peaks for aluminum are indicated in the figure below. Sketch each plane and its intercepts relative to a cubic unit cel. (to avoid confusion use a separate sketch for each plane)? 100 (11) 0.1542 nm (CuK radintion) 60 (200) 40 (220) (311) (22)(40o) (331)(420) 0 20 30 40 50 60 70 80 90 100 110 120 29 (degrees)

Answer 1

All the planes are indicated by shaded area within the cubic unit cell with corresponding intercepts.

C111) 2- →(200) (220) (311) (400 (2 222) a4 (33 ) (420)