Eur. Phys. J. B (2013) 86: 396
https://doi.org/10.1140/epjb/e2013-40564-6

Regular Article

Effect of van der Waals interactions on H₂ dissociation on clean and defected Ru(0001) surface

¹ Lappeenranta University of Technology, P.O. Box 20, 53851 Lappeenranta, Finland
² Aalto University, School of Science, Department of Applied Physics, P.O. Box 11100, 00076 Aalto, Finland

^a e-mail: mikko.puisto@lut.fi

Received: 12 June 2013
Received in final form: 5 August 2013
Published online: 25 September 2013

Abstract

Ab initio computational methods are used to study the relevance of van der Waals interactions in the case of a hydrogen molecule adsorption on the Ru(0001) surface. In addition to the clean surface, the effects of ruthenium adatom and vacancy on the process are studied. The adsorption characteristics are analyzed in terms of two dimensional cuts of the potential energy surface (PES). Based on the earlier studies for such systems, we mostly concentrate on the trajectories where the hydrogen molecule approaches the surface in parallel orientation. The results indicate that for a clean Ru(0001) the calculations applying the non-local van der Waals potentials yield higher barriers for the dissociation of the H₂ molecule. Of the high symmetry sites on Ru(0001), the top site is found to be the most reactive one. The vacancy and ruthenium adatom sites exhibit high dissociation barriers compared with the clean surface.