Dissociative adsorption of H2 using the close-coupling wave packet method

Abstract

A time-dependent quantum mechanical wave packet method was used to study the dynamics of the dissociative adsorption of H2 and D2 on a flat, static surface. A three-dimensional (3D) model was used in which the molecular rotational, vibrational, and center-of-mass translational motion normal to the surface are treated. In the close-coupling wave packet method the wave function is represented using a combination of a basis set expansion for the rotational degrees of freedom and a 2D L-shaped grid for the vibrational and translational coordinates. The time propagation is carried out by expanding the time-evolution operator in a series of Chebyshev polynomials. The molecule–surface interaction is described using a modified London–Eyring–Polanyi–Sato (LEPS) potential with parameters chosen to represent the H2/Ni(100) system. The dissociation probability was calculated for different incident energies and initial rotational and vibrational states and compared to the results of other theoretical calculations. Higher incident energies are required for D2 dissociation than for H2. The barrier height and zero-point energies at the saddle point can be determined from the energy dependence of the dissociation probabilities for H2 and D2.