Insensitivity of trapping at surfaces to molecular vibration

We have measured the trapping probability of NO(v = 0 and v = 2) on Au(111) as a function of translational energy of incidence. The range of translational and vibrational energies probed is comparable, yet the influence of the two types of motion is very different; 0.46 eV of translational energy is sufficient to completely suppress trapping, but the 0.46 eV of vibrational energy in NO(v = 2) has no measurable effect. The insensitivity of trapping probabilities to vibrational energy stands in sharp contrast to the strong sensitivity of direct activated dissociative adsorption to vibrational energy. (c) 2005 Elsevier B.V. All rights reserved.