Ab initio molecular dynamics of H-2 desorption from Si(100)-2x1

We present the first ab initio molecular dynamics (AIMD) trajectories of two competing mechanisms proposed for II, desorption from Si(100)-2 x 1. We show that silicon dihydride species are the most likely desorption precursors and that surface corrugation is responsible for focusing desorbing trajectories, based on comparisons with experimental dynamical data. The equal roles played by the transition state (TS) structure and post-detachment dynamics is emphasized. (C) 1997 Elsevier Science B.V.