The diffuse spots in X-ray crystal photographs

Abstract

The results of these experiments and of those in a previous paper (Bragg 1941) may be summed up in the statement that the positions and forms of the diffuse spots, so far as they have been observed, correspond closely to the geometry of the true diffraction patterns of the crystal, as calculated from first principles. The reverse is partly true: the calculated pattern shows places where diffuse spots might have been found and are not, but this does not negative the value of the correspondence that is observed. The question then arises: Why is it possible to use the diffraction formula to such effect? The formula would be applicable if there were in the crystal a sufficient number of small crystalline groups acting with some independence of each other. Any other explanation must describe a condition which simulates the effects of small groups so far as these effects have been observed.