Intermolecular interactions in optical cavities: An ab initio QED study

Intermolecular bonds are weak compared to covalent bonds, but they are strong enough to influence the properties of large molecular systems. In this work, we investigate how strong light–matter coupling inside an optical cavity can modify intermolecular forces and illustrate the varying necessity of correlation in their description. The electromagnetic field inside the cavity can modulate the ground state properties of weakly bound complexes. Tuning the field polarization and cavity frequency, the interactions can be stabilized or destabilized, and electron densities, dipole moments, and polarizabilities can be altered. We demonstrate that electron–photon correlation is fundamental to describe intermolecular interactions in strong light–matter coupling. This work proposes optical cavities as a novel tool to manipulate and control ground state properties, solvent effects, and intermolecular interactions for molecules and materials.