title: Benchmark Calculations of Three-Body Intermolecular Interactions and the Performance of Low-Cost Electronic Structure Methods.
abstract: Many-body noncovalent interactions are increasingly important in large and/or condensed-phase systems, but the current understanding of how well various models predict these interactions is limited. Here, benchmark complete-basis set coupled cluster singles, doubles, and perturbative triples (CCSD(T)) calculations have been performed to generate a new test set for three-body intermolecular interactions. This "3B-69" benchmark set includes three-body interaction energies for 69 total trimer structures, consisting of three structures from each of 23 different molecular crystals. By including structures that exhibit a variety of intermolecular interactions and packing arrangements, this set provides a stringent test for the ability of electronic structure methods to describe the correct physics involved in the interactions. Both MP2.5 (the average of second- and third-order Møller-Plesset perturbation theory) and spin-component-scaled CCSD for noncovalent interactions (SCS-MI-CCSD) perform well. MP2 handles the polarization aspects reasonably well, but it omits three-body dispersion. In contrast, many widely used density functionals corrected with three-body D3 dispersion correction perform comparatively poorly. The primary difficulty stems from the treatment of exchange and polarization in the functionals rather than from the dispersion correction, though the three-body dispersion may also be moderately underestimated by the D3 correction.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , 166 10 Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Řezáč
authors.affiliation: Department of Chemistry, University of California , Riverside, California 92521 United States.
authors.forename: Yuanhang
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , 166 10 Prague, Czech Republic.|Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Palacký University , 771 46 Olomouc, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Hobza
authors.affiliation: Department of Chemistry, University of California , Riverside, California 92521 United States.
authors.forename: Gregory J O
authors.initials: GJ
authors.lastname: Beran