Dynamical Quantum Processes of Molecular Beams at Surfaces Dissociative Adsorption of Hydro推荐.pdf

Dynamical Quantum Processes of Molecular Beams at Surfaces: Dissociative Adsorption of Hydrogen on Metal Surfaces Axel Gross Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin-Dahlem, Germany 6 9 9 1 r Abstract a M 5 1 Due to the improvement of computer power and the development of ef- v 2 ficient algorithms it is now possible to combine high-dimensional quantum 0 0 3 dynamical calculations of the dissociative adsorption of molecular beams with 0 6 reliable ab-initio potential energy surfaces (PES). In this brief review two re- 9 / cent examples of such studies of the systems H /Cu(111), where adsorption is h 2 t - l hindered by a noticeable energy barrier, and H /Pd(100), where activated as r 2 t m well as non-activated paths to adsorption exist, are presented. The effect of : v i lateral surface corrugations on the sticking probability in the tunneling and X r a the classical regime and the role of additional parallel momentum are dis- cussed in the context of the H /Cu(111) results. For the system H /Pd(100) 2 2 it is shown that the initial decrease of the sticking probability with increasing kinetic energy, which is usually attributed to a precursor mechanism, can be explained by dynamical steering. In addition, the i