Improved Theoretical Description of the H2 Chemisorption Dynamics on the W(100) Surface

The dynamics of H-2 chemisorption on W(100) is investigated by means of molecular dynamics simulations performed on a new potential energy surface (PES) that includes nonlocal van der Waals interactions. The PES is based on density functional theory (DFT) calculations using the vdW-DF2 functional. The dissociative sticking curve is found to be in very good agreement with experiment for collision energies higher than 150 meV. At lower energies, discrepancies still exist and molecular dynamic trapping plays a significant role as suggested by experiments, but quantitative agreement still requires further investigation. The dynamics is analyzed in the light of previous results based on the PW91 functional.