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We utilize classical trajectory calculations to study the reaction dynamics of the dissociative adsorption of H 2 on the stepped Pt͑211͒ surface. The potential-energy surface has been obtained through an accurate interpolation of density-functional theory data at the generalized gradient approximation level, using the corrugation reduction procedure. New techniques for visualizing the collective dynamics of trajectories are introduced to elucidate the reaction mechanisms involved. Reaction exhibits a nonmonotonic dependence on collision energy, first decreasing with energy, and then increasing. A strong component of direct nonactivated reaction exists at the top edge of the step over the entire range of energies. The inverse relationship between reaction and collision energy at low energies is attributed to trapping in weak chemisorption wells. These wells also influence the direct reaction at the step, leading to a strong asymmetric dependence on incidence angle. Reaction on the terrace is activated, and only contributes significantly at high energies. Agreement with experiments on Pt͑533͒ ͓A. T. Gee, B. E. Hayden, C. Mormiche, and T. S. Nunney, J. Chem. Phys. 112, 7660 ͑2000͒; Surf. Sci. 512, 165 ͑2002͔͒ is good, and we are able to suggest new interpretations of the experimental data.

Recent theoretical progress in gas-surface reaction dynamics, a field relevant to heterogeneous catalysis, is described. One of the most fundamental reactions, the dissociative chemisorption of H2 on metal surfaces, can now be treated accurately using quantum mechanics. Density functional theory is used to compute the molecule-surface interaction, and the motion of the hydrogen atoms is simulated using quantum dynamics, modeling all six molecular degrees of freedom. Theory is in good quantitative agreement with molecular beam experiments, offering useful interpretations, and allowing reliable predictions. The success of the approach calls for extensions to larger systems, such as dissociative chemisorption of polyatomic molecules.

Articles you may be interested inReactive scattering of H2 from Cu(100): Comparison of dynamics calculations based on the specific reaction parameter approach to density functional theory with experiment J. Chem. Phys. 138, 044708 (2013); 10.1063/1.4776224Theoretical evidence for nonadiabatic vibrational deexcitation in H 2 ( D 2 ) state-to-state scattering from Cu ( 100 ) A comparison between experiment and theory is performed for the scattering of (vϭ1, jϭ1) H 2 from Cu͑100͒ at normal incidence. Experimentally, this system was studied using molecular beam techniques, with stimulated Raman pumping employed to overpopulate (vϭ1, jϭ1) in the incident beam, and resonance enhanced multi-photon ionization used to detect the H 2 scattered in two (vϭ1, j) states, and two (vϭ0, j) states. Theoretically, six-dimensional wave packet calculations were performed, employing a new, extended potential energy surface that was computed with density functional theory, using the generalized gradient approximation and a slab representation of the metal surface. Theory and experiment are in good agreement for the survival probability, i.e., the probability for rovibrationally elastic scattering. However, the theory overestimates the probabilities for rotationally inelastic scattering ͑to vϭ1, jϭ3) and for rovibrationally inelastic scattering ͑to vϭ0, jϭ5 and 7͒ for channels that could be determined experimentally. The cause of these discrepancies is discussed, as are possibilities for future improvements in the theory as well as the experiment.