Mail:
Dept. of Chemistry
Ohio State University
100 W. 18th Ave.
Columbus, OH 43210
Office:
412 CBEC
Email:
herbert@
chemistry.ohio-state.edu
Symmetry-adapted perturbation theory (SAPT) provides a chemically meaningful energy decomposition scheme for non-bonded interactions that is useful for interpretive purposes. Although formally a dimer theory, we have previously introduced an "extended" version (XSAPT) that incorporates many-body polarization via self-consistent charge embedding. Here, we extend the XSAPT methodology to include nonadditive dispersion, using a modified form of the many-body dispersion (MBD) method of Tkatchenko and co-workers. Dispersion interactions beyond the pairwise atom–atom approximation improve total interaction energies even in small systems, and for large π-stacked complexes these corrections can amount to several kcal/mol. The XSAPT+MBD method introduced here achieves errors of ≤1 kcal/mol (as compared to high-level ab initio benchmarks) for the L7 data set of large dispersion-bound complexes, and ≤4 kcal/mol (as compared to experiment) for the S30L data set of host/guest complexes. This is superior to the best contemporary density-functional methods for non-covalent interactions, at comparable or lower cost. XSAPT+MBD represents a promising method for application to supramolecular assemblies, including protein/ligand binding.