Simultaneous refinement of structure and microstructure of layered materials

The recursive description of stacking in layered crystals, originally developed by Treacy et al. [ Proc. R. Soc. London Ser. A (1991), 433 , 499–520] and implemented in the DIFFaX code, is enclosed in a non-linear least-squares minimization routine and combined with additional models (of specimen-related broadening and instrumental broadening) to allow the simultaneous refinement of both structural and microstructural parameters of a layered crystal. This implementation is named DIFFaX+ . As examples, the refinements both of a simulated pattern of diamond, showing fault clustering, and of the observed powder pattern of a synthetic stoichiometric nanocrystalline chrysotile are reported.