Attenuated MP2 with a Long-Range Dispersion Correction for Treating Nonbonded Interactions

Attenuated second order Møller–Plesset theory (MP2) captures intermolecular binding energies at equilibrium geometries with high fidelity with respect to reference methods, yet must fail to reproduce dispersion energies at stretched geometries due to the removal of fully long-range dispersion. For this problem to be ameliorated, long-range correction using the VV10 van der Waals density functional is added to attenuated MP2, capturing short-range correlation with attenuated MP2 and long-range dispersion with VV10. Attenuated MP2 with long-range VV10 dispersion in the aug-cc-pVTZ (aTZ) basis set, MP2-V­(terfc, aTZ), is parametrized for noncovalent interactions using the S66 database and tested on a variety of noncovalent databases, describing potential energy surfaces and equilibrium binding energies equally well. Further, a spin-component scaled (SCS) version, SCS-MP2-V­(2terfc, aTZ), is produced using the W4-11 database as a supplemental thermochemistry training set, and the resulting method reproduces the quality of MP2-V­(terfc, aTZ) for noncovalent interactions and exceeds the performance of SCS-MP2/aTZ for thermochemistry.