Accurate and Efficient Method for Many-Body van der Waals Interactions

Alexandre Tkatchenko
Seminar

Van der Waals (vdW) interactions are ubiquitous in nature, playing a major role in defining the structure, stability, and function for a wide variety of molecules and materials.
Thus, the accurate description of vdW interactions is essential for improving our understanding of many biological, chemical, and (hard and soft) condensed matter.
Here I present our recent developments of an efficient method to determine the full long-range many-body vdW energy for molecules and solids. This is achieved by combining the TS-vdW method (Phys. Rev. Lett. 102, 073005 (2009)) with the self-consistent screening equation of classical electrodynamics. This leads to a seamless description of anisotropy, polarization, and depolarization for the polarizability tensor of molecules and solids. The screened long-range many-body van der Waals (vdW) energy is obtained from the numerically exact solution of the Schroedinger equation for a system of coupled oscillators. We show that the screening and the many-body vdW energy play a significant role even for rather small molecules, becoming crucial for an accurate treatment of conformational energies in bio-molecules, and binding of molecular crystals. The computational cost of the developed theory is negligible compared to the underlying electronic structure calculation, enabling calculations for thousands of atoms.