Quantifying intermolecular interactions and their use in computational crystal structure prediction

Intermolecular interactions control the crystal structures adopted by rigid organic molecules. Methods of quantifying the intermolecular forces from the ab initio charge density of the molecule have been extended to organic molecules, albeit more approximately than for small polyatomics. This has led to some almost non-empirical models being used to study organic packing, including crystal structure prediction studies. These studies are highlighted, with particular emphasis on what they reveal about the transferability assumptions that underpin the use of empirical atom-atom intermolecular potentials and intuitive crystal design.