Enhanced reactivity of highly vibrationally excited molecules on metal surfaces

The chemical dynamics of highly vibrationally excited molecules have been s tudied by measuring the quantum state-resolved scattering probabilities of nitric oxide (Nd) molecules on clean and oxygen-covered copper (111) surfac es, where the incident NO was prepared in single quantum states with vibrat ional energies of as much as 300 kilojoules per mole. The dependence of vib rationally elastic and inelastic scattering on oxygen coverage strongly sug gests that highly excited NO (v = 13 and 15) reacts on clean copper (111) w ith a probability of 0.87 +/- 0.05, more than three orders of magnitude gre ater than the reaction probability of ground-state NO. Vibrational promotio n of surface chemistry on metals (up to near-unit reaction probability) is possible despite the expected efficient relaxation of vibrational energy at metal surfaces.