Elephant, Blind Men, Molecule - Surface Scattering and Surface Chemistry

Understanding the mechanism of energy transfer from a molecule to a metal surface is essential for building an atomic/molecular level description of surface chemistry. In this talk I will describe some general ideas regarding how a molecule exchanges translational, rotational and vibrational energy when it interacts with a metal surface. I will discuss this in the context of some of our recent work based on quantum state resolved inelastic scattering experiments of diatomic molecules such as: CO, NO and HCl scattering from Au(111) surface.

Further, I will also talk about the process of dissociation of a molecule on a metal surface using some of our recent work on the HCl/Au(111) system as an example. Our study of this process points towards serious limitations in the the currently available state of the art theoretical methods. These methods, based on 6-D quantum dynamical simulations using density functional theory based potential energy surface, relying on the Born-Oppenheimer and the rigid surface approximation which have worked well in describing previously well studied dissociation process such as H2 on Cu(111) and N2 on Ru(0001), severely overestimate the dissociation probability when compared to our experiments.