Accuracy of Density Functional Theory calculations in the dissociation of N2 molecules on W(110)

G.A. BOCAN; M. ALDUCIN; R.DÍEZ MUIÑO; H.F. BUSNENGO; A. SALIN

Estocolmo, Suecia

Conferencia; XIII International Conference on Surface Science; 2007

ICSS

Resumen <!-- @page { margin: 0.79in } P { margin-bottom: 0.08in } --> The six-dimensional potential energy surface for the dissociation of N2 molecules on W(110) was recently calculated using density functional theory and the corrugation reduction procedure [1]. Classical dynamics on this potential energy surface showed two distinct channels contributing to the dissociation process, namely, a direct one and an indirect one. The theoretical results for the sticking coefficient at low coverage compared well with experimental measurements at 800K, exception made of the range of incident energies in which the indirect channel prevails. Here, we show that the dissociation dynamics of N2 on W(110) for this particular energy range is very sensitive to the details of the potential energy surface. In particular, we recalculate the full multidimensional potential energy surface using a different exchange-correlation functional and study the effect of this modification in the dissociation dynamics. The weight of the indirect channel is shown to be dramatically diminished in the new calculation. The role of dynamical studies in the optimization of density functional theory calculations for this kind of problems is discussed. [1] M. Alducin, R. Díez Muiño, H. F. Busnengo, and A. Salin, Phys. Rev. Lett. 97, 056102 (2006).