An exhaustive molecular beam study of methane dissociation on Pt{110}(1 x 2
) provides a new data base for modeling this process. Major new features in
clude a sharp rise in dissociative sticking probability, s(o), with increas
ing translational energy, E-t, corresponding to a barrier of 238 meV, a dra
matic increase in s(o) at higher E-t with increasing vibrational energy, an
d a significant rise in s(o) as E-t is lowered below similar to 100 meV. It
is concluded that the low energy process is a distinctive steering-assiste
d direct adsorption pathway.