Surface temperature dependence of rotational excitation of H2 scattered from Pd(111) -: art. no. 127601

Classical dynamics simulations are performed to study rotational excitation of H-2 scattered from Pd(111), taking into account energy exchange with surface phonons through a 3D surface oscillator model. We show that dynamic trapping, identified recently in the study of dissociation dynamics, plays a prominent role. The corresponding long interaction time due to several recollisions allows an efficient energy exchange between H-2 molecules and surface phonons. This microscopic mechanism explains, the puzzling experimental finding on the role of surface temperature in H-2(nu = 0, J = 1 --> 3) excitation.