Rings sliding on a honeycomb network: Adsorption contours, interactions, and assembly of benzene on Cu(111)

Abstract

Using a van der Waals density functional (vdW-DF) (Phys. Rev. Lett. 92, 246401 (2004)), we perform ab initio calculations for the adsorption energy of benzene (Bz) on Cu(111) as a function of lateral position and height. We find that the vdW-DF inclusion of nonlocal correlations (responsible for dispersive interactions) changes the relative stability of eight binding-position options and increases the binding energy by over an order of magnitude, achieving good agreement with experiment. The admolecules can move almost freely along a honeycomb web of “corridors” passing between fcc and hcp hollow sites via bridge sites.