Quantum Dynamics of H<INF>2</INF>−Surface Scattering:  H<INF>2</INF> + LiF(001) and H<INF>2</INF> + Cu(100)

We consider the scattering of H<INF>2</INF> from surfaces for two benchmark systems. The system H<INF>2</INF> + LiF(001) is the classical example of hydrogen scattering off an ionic surface. Quantum dynamical calculations employing a new model potential and experiments have shown that the electrostatic interaction between the molecule's quadrupole moment and the surface ions has a crucial influence on the scattering in this system. The results suggest that the ionicity of the surface ions in ionic surfaces can be probed by scattering H<INF>2</INF> of these surfaces, for instance, by measuring the differences between diffraction of cold p-H<INF>2</INF> and cold o-H<INF>2</INF>. The system H<INF>2</INF> + Cu is the classic example of activated dissociative chemisorption. It is now possible to perform quantum dynamical calculations on fully activated dissociative chemisorption in which all molecular degrees of freedom are treated without dynamical approximations, as here illustrated for H<INF>2</INF> + Cu(100). This development makes it possible to evaluate the accuracy of electronic structure methods for molecule−surface interactions, to help interpret trends in the reactivity observed experimentally, and to arrive at new predictions for experiments.