Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 12: Inorganic/Organic Interfaces: Growth II

O 12.1: Talk

Monday, March 16, 2015, 15:00–15:15, MA 005

Many-Body Dispersion Effects in the Adsorption of Atoms and Molecules at Metal Surfaces — •Victor Ruiz and Alexandre Tkatchenko — Fritz-Haber-Institut der MPG, Theory Department, Berlin, Germany

Van der Waals (vdW) interactions play an essential role in the structure and stability of atoms and molecules adsorbed at inorganic surfaces. Several promising methods have been developed in recent years for an efficient modeling of these ubiquitous interactions in molecules and solids. However, most of these methods are still based on an effective pairwise treatment of vdW interactions, ignoring the often important many-body contributions to the vdW energy. Here we show that the inclusion of many-body effects in vdW interactions enables us to achieve quantitative predictions in the adsorption energies of atoms and molecules on metal substrates. For this, we employ the recently developed many-body dispersion method coupled with density-functional theory (DFT+MBD) [1,2], which includes many-body effects in the long-range correlation energy to all orders in the dipole approximation. We study the influence of MBD effects on the adsorption structures, energies, and perpendicular vibrational frequencies of a Xe monolayer on transition metal surfaces. We futher study the adsoption of PTCDA (C₂₄H₈O₆) on Au(111), and compare to recent measurements of the adsorption energy and vertical adsorption height. [1] Phys. Rev. Lett. 108, 236402 (2012); [2] J. Chem. Phys. 140, 18A508 (2014).