Analysis of Single-Crystal Diffuse X-Ray Scattering via Automatic Refinement of a Monte Carlo Model

Abstract

Although diffuse scattering from disordered crystals has been known since the earliest days of X-ray diffraction its interpretation and analysis is still far from being a routine process and quantitative studies are relatively rare. The most extensive and quantitative methods have been developed in the field of alloys and simple oxides where the number of parameters needed to define a disordered structure is small and the diffracted patterns can be attributed unambiguously to basic interatomic interactions’. For structures containing more than a few atoms, however, this type of detailed analysis is simply not feasible, and alternative approaches must be adopted (see e.g. the reviews by Welberry & Butler^sand Frey⁶’⁷). For large (macromolecular) structures interpreting diffuse scattering, when the structure contains so many parameters, would appear to be a quite intractible problem; but even here useful information can be extracted^8-11. The present work forms part of a long-term study to develop methods that will allow routine analysis of diffuse scattering for a diverse range of materials.