Vibrational excitation and deexcitation rates of molecules adsorbed on metal surfaces

Abstract

The rates for vibrational excitation and deexcitation of adsorbed molecules on metal surfaces are reported. The desorption of the adsorbed molecules is shown to compete with the excitation process, resulting in ‘‘vibrationally cold’’ desorbing molecules. Simple rate equations, together with the available experimental data, are used to estimate the rates for vibrational excitation and deexcitation of NO molecules on Pt(111) surfaces as a function of the crystal temperature. The application of this approach to other systems is discussed.

Electron hole pair mediated vibrational excitation in CO scattering from Au(111): Incidence energy and surface temperature dependence

“…Such an effect indeed has been reported for NO desorbing from Pt(111). 24 However, to the best of our knowledge the vibrational relaxation time for CO adsorbed on Au(111) is not known. More importantly, whether vibrational relaxation timescales are of the order of picoseconds for all metal molecule systems, irrespective of the strength of the interaction (physisorption vs. chemisorption) is an open question still.…”

Monte Carlo wave packet study of negative ion mediated vibrationally inelastic scattering of NO from the metal surface

“…6,7 In addition, relaxation may occur as a result of temporary trapping that allows the molecule to equilibrate with the substrate. 8 In reality, of course, multiple mechanisms might coexist in a scattering event.…”