IFIR   05409
INSTITUTO DE FISICA DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
DFT study of H2 adsorption on V(111)
Autor/es:
RAMOS ACEVEDO, M; BUSNEGO, H.F.; MARTÍNEZ, A.E.
Lugar:
Bordeaux
Reunión:
Workshop; - 3rd edition; 2010
Institución organizadora:
Universite Bordeaux I
Resumen:
p { margin-bottom: 0.21cm; }
The
dynamics of dissociative adsorption of H2
on the V(111) surface has been studied from the experimental side. The adsorption process has been reported to be dominated by
dynamical steering at low beam energies, but by direct chemisorption
at higher energies.
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.