Adsorption geometry of benzene on Pd(110): Results of first-principles calculations

The atomic structure of the Pd(110)-c(4 x 2)-benzene system has been determ ined by means of ab initio slab calculations. A C-2 low-symmetry equilibriu m configuration is predicted. The corresponding azimuthal angle theta simil ar to 11 degrees of the adsorbed molecule is partly due to lateral interact ions. The aromatic ring looses planar geometry and the C-H, bonds bend away from the metal. STM images calculated for the C-2 configuration are compat ible with recent experimental data.