Dispersion-corrected MP2 for improved descriptions of inter- and intramolecular interactions in organic molecular crystals

Reliably modeling polymorphic molecular crystals requires a careful balance between intra- and intermolecular interactions. Density-functional theory models have made tremendous progress in modeling such interactions, but a number of failures for conformational polymorphs and other systems can be found in the literature. A dispersion-corrected MP2 model, MP2D, will be presented which provides more accurate descriptions of non-covalent interactions in these challenging polymorphic crystals. The MP2D dispersion correction is expressed in terms of atom-centered dispersion coefficients which are computed via Grimme's D3 scheme. This approach has the benefits that the dispersion correction can be computed for any organic system with negligible computational cost, it can be applied to both intra- and intermolecular interactions, and analytical gradients can be implemented trivially. The performance of MP2D for both benchmark data sets and in challenging polymorphich molecular crystals will be presented.