THE DYNAMICS OF DEUTERIUM ADSORPTION ON Pt{100} AND THE ROLE OF ADSORBATE-INDUCED DEFECTS

Abstract

The dissociative initial sticking probability, s0, for deuterium on Pt{100}-hex has been measured as a function of beam kinetic energy, Ek, and substrate temperature, T S . At TS=150 K, s was found to increase with increasing Ek consistent with direct activated adsorption; the increase is approximately linear. At Ek=0.063 eV , s0 is independent of substrate temperature (s0≈0.07) over the range 150 to 1000 K, also consistent with a direct adsorption process. We present evidence for an increase of s0 due to adsorbate-induced defects. These defects survive annealing to 500 K but do not survive annealing to 1030 K. We have also measured s for D 2 on the (1×1) bulk truncated surface, and find it to be similar to that for the hex-reconstructed phase.