Coverage dependence of the dissociative sticking probability of methane on Pt{1 1 0}-(1×2)

The coverage dependence of the dissociative sticking probability for CH4 on Pt{1 1 0}-(1×2) has been directly determined using a high intensity supersonic molecular beam with a modified King and Wells method. We observe two distinct behaviour regions, one above 500 K and the other below 400 K. In the low temperature regime, the sticking probability drops nearly three times as fast as in the high temperature regime; this is shown to be a result of the different stable dissociation products, CHa and Ca, respectively. In both regimes, the sticking probability decreases linearly at low coverages and more slowly as the coverage increases.