title: Optimal pi-stacking interaction energies in parallel-displaced aryl/aryl dimers are predicted by the dimer heavy atom count.
abstract: It is generally accepted that large basis sets are required for the accurate calculation of interaction energies for weakly bound aryl dimers, but it has recently been reported that MP2(full)/6-31G* energies, although inaccurate in absolute terms, are well-correlated with estimated CCSD(T)/CBS results. It is now shown that this correlation holds for MP2/aug-cc-pVDZ and SCS-MP2/aug-cc-pVDZ values. Linear regression of published CCSD(T)/CBS results with MP2 or SCS-MP2 results has been used to correct systematic errors observed with both MP2 theories, and these corrections are applied to 27 parallel-displaced aromatic dimers of interest in medicinal chemistry. The optimal computed interaction energies are found to be strongly correlated with the heavy atom counts of the aryl/aryl dimers. This relationship between heavy atom count and interaction energy also applies to a series of 12 aryl/non-aryl dimers such that a single linear regression equation accounts for all of the dimers studied.
authors.affiliation: Department of Chemistry Modeling and Informatics, Merck Research Laboratories, West Point, Pennsylvania 19486, USA. john_sanders@merck.com
authors.forename: John M
authors.initials: JM
authors.lastname: Sanders
mesh_terms: D001554:Benzene / Q000737:chemistry*; D019281:Dimerization; D008958:Models, Molecular; D008968:Molecular Conformation; D013816:Thermodynamics
chemical_list: D001554:Benzene