Light-Optical Analogs of X-Ray Diffraction Patterns

Masks containing repeating arrays of holes were prepared to simulate the molecular structure of arbitrary crystals. These masks, after photographic reduction, were used for Fraunhofer-type light diffraction and the resulting diffraction patterns compared with x-ray diagrams. This procedure was evaluated from two points of view: (1) it facilitates the teaching of fundamental processes of x-ray diffraction, and (2) it shows that terms like “regularity” or “randomness” of the arrangement of crystallites apply to at least two different levels of organization: The structure of individual crystallites and the distribution and/or orientation of different crystallites relative to each other.