Poisoning of hydrogen dissociation at Pd (100) by adsorbed sulfur studied by ab-initio quantum dynamics and ab-initio molecular dynamics

SURFACE SCIENCE

卷:416

Letter

Gross, A ; Wei, CM ; Scheffler, M

关键词: chemisorption;    density functional calculations;    hydrogen;    models of surface chemical reactions;    molecular dynamics;    molecule-solid reactions;    palladium;    quantum effects;    sulfur;   

DOI  :  10.1016/S0039-6028(98)00649-9

来源: Elsevier

【 摘 要 】

We report calculations of the dissociative adsorption of H-2 at Pd (100) covered with 1/4 monolayer of sulfur using quantum dynamics as well as molecular dynamics and taking all six degrees of freedom of the two H atoms fully into account. The ab-initio potential-energy surface (PES) is found to be very strongly corrugated. In particular, we discuss the influence of tunneling, zero-point vibrations due to the localization of the wave function of the nuclei when narrow valleys of the PES are passed, steering of the approaching H-2 molecules towards low-energy barrier configurations, and the important role of subsurface absorbates for the hydrogen dissociation. It is shown that established concepts derived from low-dimensional dynamical studies are not necessarily valid in a high-dimensional treatment. (C) 1998 Elsevier Science B.V. All rights reserved.

【 授权许可】

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