Rotational effects in dissociation of H2 on Pd(111): Quantum and classical study

Abstract

High-dimensional quantum dynamical study of the dissociation of H 2 on Pd(110)

Away from generalized gradient approximation: Orbital-dependent exchange-correlation functionals

“…Although a rigorous treatment of rotational effects would require quantum mechanics, classical trajectories have been shown to adequately reproduce reaction dynamics of rotationally hot molecules in many systems, both activated [31][32][33][34] and nonactivated. 16,17,35 The classical approach has the advantage of being less computationally demanding and allows for easier physical interpretation of results; however, there are some drawbacks that must be considered.…”

“…5͑a͔͒. 16,32,[37][38][39] In the HE range, the dissociation is predominantly direct in nature, while in the LE range the direct and indirect components both contribute ͓Fig. 5͑b͔͒.…”

“…Classical trajectories are known to behave better than quasiclassical trajectories for nonactivated systems. 16,36 The initial rotational state of the molecules was set in one of the two ways. For degeneracy-averaged calculations, the angular momentum ͑L͒ of each molecule was chosen to give a rotational energy equal to that of the corresponding quantum state:…”

“…The Pd͑111͒ surface, in particular, which also exhibits a nonmonotonic dependence of reaction on collision energy, has been thoroughly investigated both theoretically and experimentally. [13][14][15][16][17] Experiments have demonstrated a large reduction in the sticking coefficient for rotationally hot molecules. 13 It was suggested that this supported the existence of dynamical steering effects, because rotating molecules are less easily oriented by steering forces toward a geometry favorable for reaction.…”

“…16 They found that dynamical trapping plays an important role in the dissociation of H 2 on Pd͑111͒, promoting reaction at low collision energies. Using quantum and classical dynamics calculations, Busnengo has also found that for low rotational states, trapping is mainly due to translational ͑T͒-to-rotational ͑R͒ energy transfer.…”