Probing exchange-correlation functionals in the dynamics of N2 dissociation on W surfaces.

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

JOURNAL OF CHEMICAL PHYSICS

AMER INST PHYSICS

Año: 2008 vol. 128 p. 154704 - 154711

0021-9606

We study the dissociative adsorption of N2 on W(100) and W(110) by means of density functional theory and classical dynamics. Working with a full six-dimensional adiabatic potential energy surface PES , we find that the theoretical results of the dynamical problem strongly depend on the choice of approximate exchange-correlation functional for the determination of the PES. We consider the Perdew-Wang-91 [Perdew et al., Phys. Rev. B 46, 6671 (1992)] and Perdew-Burke-Ernzerhof RPBE [Hammer et al., Phys. Rev. B 59, 7413 (1999)] functionals and carry out a systematic comparison between the dynamics determined by the respective PESs. Even though it has been shown in earlier works that the RPBE may provide better values for the chemisorption energies, our study brings evidence that it gives rise to a PES with excessive repulsion far from the surface.