(a) Dissociation probabilities computed for (ν = 0, j = 0) D2 + Pt(111) with quantum dynamics and with the QCT method are shown as a function of the collision energy, for normal incidence. The results are compared with sticking probabilities measured for D2 + Pt(111) [Luntz1990] and shown as a function of average incidence energy. (b) Dissociation probabilities computed for (ν = 0, j = 0) D2 + Pt(111) with the QCT method for specific collision energies are compared with sticking probabilities computed for D2 + Pt(111) with full averaging over the rovibrational state populations and velocity distributions of typical molecular beams of pure D2.