Exploring local disorder in single crystals by means of the three-dimensional pair distribution function

Abstract

Pair distribution function (PDF) analysis, based on experimental X-ray or neutron diffraction data of crystalline powders, provides an insight into structural disorder of complex materials. However, the observation of interatomic vectors is confined to their norms. Based on three-dimensional single crystal X-ray diffraction data, the methodical approach presented here is an upgrade of current PDF analysis that considers the effective spatial orientation of interatomic vectors and, thus, provides a basis for a better and direct understanding of the structural composition of complex crystalline materials. The usability of three-dimensional difference PDF analysis is exemplified by the disordered structure of N,N′,N″-tris-t-butyl-1,3,5-benzene tricarboxamide.