DFT study of H2 adsorption on V(111)

MAXIMILIANO RAMOS ACEVEDO; ALEJANDRA ELISA MARTÍNEZ; HERIBERTO FABIO BUSNENGO

Bordeaux

Congreso; III Elementary Reactive Processes at Surfaces; 2010

The present work is intended to theoretically describe the dissociative adsorption process of H2 molecules on a V(111) surface. The description of the molecule-surface interaction is carried out through DFT electronic structure calculations at the GGA level, the exchange-correlation energy being described with the PW91 functional. A plane wave basis set is employed for the electronic orbitals and PAW pseudopotentials are used to describe the interaction with the atomic cores. The slab/supercell aproximation and 2D periodic boundary conditions are applied to model the surface.A complete characterization of the clean V(111) surface structure is presented, considering the slab thickness, its relaxation and the possibility of top-most layer reconstruction. Moreover, spin-polarized calculations were computed to gauge to what extent the magnetic degrees of freedom are relevant in the surface description.The relative stability of different adsorption sites for atomic H over the surface is studied, as well as the global energetics of the dissociation process and the activation energies for H2/V(111). In the latter case 2D (Z,r) cuts of the potential energy surface of H2/V(111) and reaction pathways are analized.A continuos representation of the 6D PES is obtained by using the Corrugation Reducing Procedure (CRP). Classical trajectories dynamical calculations based on this 6D PES are carried out to study the dissociative adsorption reaction. The comparison with available experimental data is presented.