Many-Body van der Waals Effects in Advanced Materials

Van der Waals (vdW) interactions are ubiquitous in molecules and condensed matter. These interactions are inherently quantum mechanical phenomena that arise from concerted correlations between many electrons within a given molecular system. Despite this fact, the vast majority of theoretical calculations include long-range vdW interactions based on a simple effective interatomic pairwise model. We introduce an efficient method that accurately describes the full long-range many-body vdW energy [1,2], and demonstrate that many-body contributions can significantly exceed the highly coveted ``chemical accuracy''. Cases studied include intermolecular binding energies, the conformational hierarchy of DNA structures [2], the geometry and stability of molecular crystals [1], and supramolecular host--guest complexes [3]. Our findings suggest that inclusion of the many-body vdW energy is essential for achieving chemical accuracy and therefore must be accounted for when studying advanced materials. [1] Tkatchenko, DiStasio, Car, Scheffler, PRL (2012), [2] DiStasio, von Lilienfeld, Tkatchenko, PNAS (2012), [3] Tkatchenko, Alfe, Kim, JCTC (2012).