Multi-Coefficient Extrapolated DFT Studies of π···π Interactions: The Benzene Dimer (original) (raw)

We report tests of new (2005) and established (1999-2003) multi-level methods against essentially converged benchmark results for nonbonded π···π interactions in benzene dimers. We found that the newly developed multi-coefficient extrapolated density function theory (DFT) methods (which combine DFT with correlated wave function methods) give better performance than multilevel methods such as G3SX, G3SX(MP3) and CBS-QB3 that are based purely on wave function theory (WFT); furthermore they have a lower computational cost. We conclude that our empirical approach for combining WFT methods with DFT methods is a very efficient and effective way for describing not only covalent interactions (as shown previously) but also nonbonded interactions.