A new six-dimensional potential energy surface for NO/Au(111).

In this contribution, we reinvestigate the interaction of nitric oxide with a gold(111) surface using plane-wave density functional theory, with particular emphasis on the role of intermode coupling. A new global representation of the potential energy surface is obtained from the ab initio data by non-linear adjustment, yielding a set of physically motivated parameters. The novel functional form improves on its parent [Marquardt et al. J. Chem. Phys. 132, 074108 (2010)] by addressing the variation of the charge transfer character of the electronic structure data, and by treating surface corrugation via translationally invariant weighting functions of lower-dimensional, high-symmetry sites. Contrary to previous studies, the adsorption minimum does not favour the hollow sites and is found at a strongly tilted orientation (circa 60) on top of a gold atom of the topmost layer. High-dimensional anharmonic vibrational analysis performed using a Lanczos-based contracted iterative procedure reveals that the low-lying excited vibrational states retain a strongly tilted orientation and remain predominantly localised at the atop site. These findings are expected to have important implications for the interpretation of recent NO scattering experiments. [ABSTRACT FROM AUTHOR]