Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 51: Focussed Session: Frontiers of Electronic Structure Theory V (jointly with HL and TT)
O 51.11: Talk
Wednesday, March 13, 2013, 18:45–19:00, H36
Many-Body van der Waals Interactions from Isotropically Damped Coupled Quantum Harmonic Oscillators — •Alberto Ambrosetti1, Robert A. DiStasio Jr.2, and Alexandre Tkatchenko1 — 1Fritz-Haber institut der MPG, Faradayweg 4-6 14195 Berlin, Germany — 2Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
The current interest in functional materials with increasing size and complexity demands high accuracy in first-principles calculations. In these systems, the collective many-body (MB) description of van der Waals (vdW) interactions is indispensable to reach the highly coveted “chemical accuracy”. The recently introduced DFT+MBD method (PRL 108, 236402 (2012); PNAS 109 14791 (2012)) for the dispersion energy based on a coupled set of quantum harmonic oscillators (QHOs) was shown to reach chemical accuracy for gas-phase molecules and molecular solids. Its formulation, however, makes the derivation of interatomic forces and a fully self-consistent DFT+MBD implementation non-trivial. We propose here a simplified approach, making use of a set of QHOs with isotropically damped dipole–dipole coupling, which provides an effective random-phase approximation treatment of their vdW interaction (arXiv:1210.8343). This allows for a simple analytical treatment of interatomic forces, yet providing high efficiency and accuracy. Application over a wide range of systems shows a consistent improvement with respect to pairwise approximations, particularly for the most extended systems.