Observation of direct vibrational excitation in gas-surface collisions: NO on ag(111)

Vibrationally excited NO molecules have been observed in the scattering of NO(v=0) from Ag(111). A direct mechanism is inferred based on the observation of v=1 angular distributions, which are quasispecular, and rotational-state distributions, which depend on beam energy. Vibrational excitation is found to depend strongly on surface temperature, TS, and relatively weakly on incident kinetic energy, E, reaching (75)% at TS=760 K and E=120 kJ mol-1. These results are discussed in terms of an electronic mechanism for vibrational excitation. © 1985 The American Physical Society.