London Dispersion Interactions Imitate Pressure for Molecular Crystals

The packing of molecular crystals,in which the constituent molecularunits have no directional forces, is primarily controlled by weakLondon dispersion (LD) forces. These forces assist in stabilizingthe system by bringing the molecular units into the proximity of eachother. In this paper, the same effect is shown to be externally inducedby pressure. The minimal pressure required to correctly describe thecrystal structure without LD interactions (P (LD)) provides a quantifiable measure for the weak intermolecularinteractions. LD forces are shown to be essential for an accuratedescription of the pressure-induced phase transitions across examplesof linear, trigonal-planar, square-planar, tetrahedral, trigonal bipyramidal,and octahedral molecules.

Automated summary

The packing of molecular crystals is primarily controlled by weak London dispersion forces, which bring the molecular units into proximity to stabilize the system. This paper demonstrates that the same effect can be induced by external pressure. The minimal pressure required to accurately describe the crystal structure without LD interactions serves as a quantifiable measure for the weak intermolecular interactions. LD forces are shown to be essential for an accurate description of pressure-induced phase transitions across various types of molecules.