FORWARD LIGHT-SCATTERING FOR ARBITRARY SHARP-EDGED CONVEX CRYSTALS INFRAUNHOFER AND ANOMALOUS DIFFRACTION APPROXIMATIONS

Fraunhofer diffraction is a well-known physical model for describing f orward light scattering from opaque particles much larger than the wav elength of the light. Analytical expressions exist for diffraction fro m circular- or rectangular-shaped apertures. An expression is derived for diffraction by apertures of a general polygonal shape. From this e xpression the exact solution for anomalous diffraction by arbitrary co nvex crystals is calculated. These expressions are useful in character izing crystal size and shape, by laser diffraction instruments, when m easured in a solution.