Europhys. Lett., 63 (4) , pp. 556-561 (2003)
Auto-catalytic effect in ammonia dissociation on surface: First-principles model studyM. Z. Zgierski and Z. K. Smedarchina
Steacie Institute for Molecular Sciences, National Research Council of Canada Ottawa, K1A 0R6 Canada
(Received 28 April 2003; accepted in final form 16 June 2003)
Density functional theory and an approximate instanton method have been applied to calculate absolute rate constants of ammonia dissociation on a model surface. It is shown that the dissociation is dominated by hydrogen atom tunneling even at room temperature, and that high coverage of the surface, when two ammonia molecules adsorb on the nearest-neighbour dimers occupying the same row, speeds up the dissociation process. This auto-catalytic effect is attributed to the modification of the buckling of the two dimers in the presence of a second ammonia molecule.
68.43.Bc - Ab initio calculations of adsorbate structure and reactions.
82.30.Lp - Decomposition reactions (pyrolysis, dissociation, and fragmentation).
82.65.+r - Surface and interface chemistry; heterogeneous catalysis at surfaces.
© EDP Sciences 2003