Achieving Pressure Consistency in Mechanochemical Simulations of Chemical Reactions Under Pressure.

The eXtended Hydrostatic Compression Force Field (X-HCFF) is a mechanochemical approach in which a cavity is used to exert hydrostatic pressure on a target system. The cavity used in this method is set up to represent the van der Waals (VDW) surface of the system by joining spheres sized according to the respective atomic VDW radii. The size of this surface can be varied via a scaling factor, and it can be shown that the compression forces exerted in X-HCFF in its current implementation depend on this factor. To address this dependency, we have developed a rescaling formalism for the applied forces, allowing us to drastically reduce the dependency of the compression forces on the chosen scaling factor. Independency from the scaling factor is important, as the scaling of the VDW spheres is often used to ensure an overlap of cavities in supramolecular complexes, which is necessary for the simulation of chemical reactions. Our rescaling formalism reduces the empiricism of the X-HCFF approach and boosts its applicability in the field of computational high-pressure chemistry.