Kinematic diffraction is insufficient to distinguish order from disorder

Abstract

Diffraction methods are at the heart of structure determination of solids. While Bragg-type scattering (pure point diffraction) is a characteristic feature of crystals and quasicrystals, it is not straightforward to interpret continuous diffraction intensities, which are generally linked to the presence of disorder. However, based on simple model systems, we demonstrate that it may be impossible to draw conclusions on the degree of order in the system from its diffraction image. In particular, we construct a family of one-dimensional binary systems which cover the entire entropy range but still share the same purely diffuse diffraction spectrum. © 2009 The American Physical Society.