Many-body van der Waals interactions beyond the dipole approximation

Long-ranged van der Waals (vdW) interactions are most often treated via Lennard-Jones approaches based on the combination of two- body and dipolar approximations. While beyond-dipole interactions and many-body contributions were separately addressed, little is known about their combined effect, especially in large molecules and relevant nanoscale systems. In this work, a full many-body description of vdW interactions beyond the dipole approximation is provided, efficiently applicable to large-scale systems. Dipole–quadrupole interactions consistently exhibit large magnitude up to nm-scale separations, while many-body effects lead to system-dependent screening effects, which can reduce vdW interactions by a large fraction. Combined many-body and multipolar terms emerge as an essential ingredient for the reliable description of vdW interactions in molecular and nanoscale systems."