Modeling of the Dissociative Adsorption Probability of the H[sub 2]-Pt(111) System Based on Molecular Dynamics

Abstract

Molecular Dynamics (MD) was used to simulate dissociative adsorption of a hydrogen molecule on the Pt(111) surface considering the movement of the surface atoms and gas molecules. The Embedded Atom Method (EAM) was applied to represent the interaction potential. The parameters of the EAM potential were determined such that the values of the dissociation barrier at different sites estimated by the EAM potential agreed with that of DFT calculation results. A number of MD simulations of gas molecules impinging on a Pt(111) surface were carried out randomly changing initial orientations, incident azimuth angles, and impinging positions on the surface with fixed initial translational energy, initial rotational energy, and incident polar angle. The number of collisions in which the gas molecule was dissociated were counted to compute the dissociation probability. The dissociation probability was analyzed and expressed by a mathematical function involving the initial conditions of the impinging molecule, namely the translational energy, rotational energy, and incident polar angle. Furthermore, the utility of the model was verified by comparing its results with raw MD simulation results of molecular beam experiments.