Methane’s dissociative chemisorption is highly activated on a range of transition metal surfaces. Internal-state-averaged and state-resolved beam-surface scattering experiments show that vibrational energy (Evib ) can be highly effective in promoting dissociative chemisorption via a direct mechanism, but evidence for Evib activation via a precursor-mediated mechanism on a metal surface remains scare. We will present recent experimental results from our lab that demonstrate the ability of Evib to promote methane dissociation via both direct and precursor mechanisms on Ir(111). These results build on prior studies of trapping-mediated reactivity on Ir(111)1 by exploring how Evib in the incident methane molecule promotes reactivity, and they are consistent with the timescales and pathways of vibrational energy flow and damping on these surfaces.

 

1. Seets, D. C., C. T. Reeves, et al. (1997). "Dissociative chemisorption of methane on Ir(111): Evidence for direct and trapping-mediated mechanisms." J. Chem. Phys. 107(23): 10229-10241.