Structure Analysis of Disorder in a Molecular Crystal with Terahertz Spectroscopy and Solid-state Density Functional Theory

This work presents a methodology of applying THz spectroscopy to solve one outstanding problem in crystallography-the structure analysis of disorder. Form I of diflunisal, which shows atomic occupational disorder, is used for the illustration. Through analyzing the roles played by disordered atoms to THz vibrations, we have retrieved concrete information about the symmetric restrictions on the spatial correlations of disordered atoms and revealed indiscriminate experimental evidence of the existence of explicit correlation patterns.