SCATTERING OF VIBRATIONALLY EXCITED H-2 FROM CU(111)

The interaction of hydrogen with a Cu(111) surface has been studied using a vibrationally hot molecular beam with state selected detection of the incident and scattered molecules by resonance-enhanced multiphoton ionisation. The ratio of the survival probability for H-2 (nu = 1, J = 1) in the specular beam to that for (nu = 0, J = 1) is 0.67 +/- 0.1 for an incident translational energy of 0.34 eV at 45-degrees incidence. This is consistent with efficient dissociative chemisorption of the H-2 (nu = 1) level, dissociation of the (nu = 0) level being negligible at this energy.