Eigenstate-Resolved Studies of Gas-Surface Reactivity:CH4(ν3) Dissociation on Ni(100)

Abstract

A new experimental technique uses state-resolved infrared laser excitation to probe a polyatomic molecule's dissociative chemisorption dynamics with previously unattainable detail. Methane molecules excited to $v\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$ of the ${\ensuremath{\nu}}_{3}$ C-H stretching vibration are up to 1600 times more reactive on a clean Ni(100) surface than are molecules in the ground vibrational state. Over a translational energy range of 27 to 54 kJ/mol, their absolute reaction probability increases from $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ to $6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, which indicates that ${\ensuremath{\nu}}_{3}$ is responsible only in part for the vibrational activation reported in previous studies.