Seamless and Accurate Modeling of Organic Molecular Materials

The near endless possibilities for
assembling molecular materials
has long posed a difficult challenge for theory. All crystal-structure
prediction methods acknowledge the crucial contribution of van der
Waals or dispersion interactions, but few go beyond a pairwise additive
description of dispersion, ignoring its many-body nature. Here we
use two databases to show how a many-body approach to dispersion can
seamlessly model both solid and gas-phase interactions within the
coveted “chemical accuracy” benchmark, while the underlying
pairwise approach fails for solid-state interactions due to the absence
of many-body polarization and energy contributions. Our results show
that recently developed methods that treat the truly collective nature
of dispersion interactions are able to reach the accuracy required
for predicting molecular materials, when coupled with nonempirical
density functionals.