Potential-energy surface forH2dissociation over Pd(100)

Abstract

The potential energy surface (PES) of dissociative adsorption of H2 on Pd(100) is investigated using density functional theory and the full-potential linear augmented plane wave (FP-LAPW) method. Several dissociation pathways are identified which have a vanishing energy barrier. A pronounced dependence of the potential energy on "cartwheel" rotations of the molecular axis is found. The calculated PES shows no indication of the presence of a precursor state in front of the surface. Both results indicate that steering effects determine the observed decrease of the sticking coefficient at low energies of the H2 molecules. We show that the topology of the PES is related to the dependence of the covalent H(s)-Pd(d) interactions on the orientation of the H2 molecule.

Hydrogen dissociation on metal surfaces - a model system for reactions on surfaces

“…7c and d. While the dissociation path over the Pd on-top position on the clean surface is hindered by a barrier of height 0.15 eV [4] (Fig. 4b), the adsorbed sulfur leads to an increase in this barrier height to 1.3 eV (Fig.…”

“…There are many different ways of illustrating the electronic factors that determine the reactivity of a particular system (see, e.g., Refs. [4,7,43,51,52]). Current studies have emphasized that the reactivity of surfaces cannot be solely understood by the electronic density of states at the Fermi level [53,54].…”

“…In particular in the theoretical description there has been much progress recently due to the improvement of computer power and the development of efficient algorithms. It has become possible to map out detailed potential energy surfaces of the dissociation of hydrogen on metal surfaces by density functional theory calculations [1][2][3][4][5][6][7][8]. The availability of high-dimensional reliable potential energy surfaces has challenged the dynamics community to improve their methods in order to perform high-dimensional dynamical studies on these potentials.…”

Direct subsurface absorption of hydrogen on Pd(111): Quantum mechanical calculations on a new two-dimensional potential energy surface

“…A similar finding was obtained in a study by Wilke and Scheffler on the analogous H 2 ϩPd͑100͒ system. 54 Further we have done the calculations on a 3 layer slab with the H 2 on one side. For adsorption geometries only including surface sites, already a 2 layer slab gives good results.…”

Defeitos Nativos e Impureza de Berílio em Nitreto de Boro Cúbico

“…(t~H4J superficies I15 ,16] e na obtenção de propriedades de bulk dos ma teriaisJ17,18] Trabalhos recentes de aplicação do método sào encontrados nas rererências [19][20][21][22][23][24][25][26][27][28][29][30]. O nosso trabalho representa a primeira contrIbuição desse método para o estudo de defeitos e impurezas em sernicondutores.…”