Diffuse x-ray scattering and models of disorder

Early theories of diffuse x-ray scattering from disordered crystals largely dealt with one-dimensional (1D) models and such concepts as 'correlation length' and 'domain size' are largely based on statistics of these 1D lattices. More recently, theories involving higher-dimensional models of disorder have evolved, and it is seen that the usefulness of some traditional concepts perhaps needs to be reappraised. The author reviews the earlier 1D models in order to develop the framework necessary for a discussion of the later higher-dimensional results. The theories are illustrated with optical analogue diffraction examples.