title: Coupled-cluster interaction energies for 200-atom host-guest systems.
abstract: We have developed a method to calculate interaction energies of large systems (such as host-guest or even protein-ligand systems) at the local coupled-cluster with singles, doubles, and perturbative triples level, and with extrapolation to the limit of a complete basis set. The method is based on the polarizable multipole interactions with supermolecular pairs molecular fractionation approach, which combines a pairwise quantum-mechanical evaluation of the short-range interactions with a polarizable multipole treatment of many-body effects. The method is tested for nine guest molecules binding to an octa-acid host (in total 198-207 atoms), as part of the SAMPL4 blind challenge. From the test calculations, the accuracy of the approach is found to be 10 kJ mol(-1) or better. Comparison with dispersion-corrected density functional theory reveals that the latter underestimates the dispersion contribution for this type of system, which leads to a difference in the ranking of the ligands.
authors.affiliation: Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen (Germany).
authors.forename: Milica
authors.initials: M
authors.lastname: Andrejić
authors.forename: Ulf
authors.initials: U
authors.lastname: Ryde
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Mata
authors.forename: Pär
authors.initials: P
authors.lastname: Söderhjelm
keywords: cluster compounds; ligand binding; molecular fractionation; polarizable force fields; quantum chemistry