Translational Inelasticity of NO and CO in Scattering from Ultrathin Metallic Films of Ag/Au(111)

Abstract

We investigated translational inelasticity in molecular beam surface scattering of NO and CO from ultrathin metallic films of Ag with atomically defined thicknesses grown on single-crystal Au(111). For both molecules, we observe a gradual decrease of the mean final translational energy for Ag film thicknesses between 0 and 3 ML after which no thickness dependence is seen. For Ag films with thicknesses greater than 3 ML, observations are indistinguishable from those of scattering experiments performed on pure Ag crystal surfaces. The similar behavior of both molecules suggests that translational inelasticity is dominated by the mechanical properties of the surface. Theory predicts a thickness-dependent trend of the phonon spectrum that can qualitatively explain the observed behavior.

Alignment-resolved O2 scattering from highly oriented pyrolytic graphite and LiF(001) surfaces

“…State-resolved molecular beam-surface scattering experiments, which specify the geometry and internal states of incident and/or scattered molecules, provide valuable information not only on the geometrical effect in the molecule-surface interaction, but also on the mechanism of energy dissipation of impinging molecules necessary to result in trapping or chemisorption [1][2][3][4][5][6]. The geometrical effect here is usually classified into two categories.…”

Ab initio molecular dynamics simulations of molecular scattering from metal(111) surfaces

“…Thus the differences in the phonon motion of the surfaces lead to different couplings to the translational dof of the molecule. The results reported in this chapter were mostly published in [39].…”

“…The investigation of S T E I N S I E K et al [39] shows strong difference in the translational inelasticity of scattered CO and NO from pure and Ag-coated Au (111) surfaces. As the reason for these observations was not clear different aspects which may influence them were investigated here.…”

“…More recently, scattering experiments for CO in low [39][40][41] and high [42,43] vibrational states and different metal (111)-surfaces were carried out. These experiments reveal that the vibrational relaxation of CO(v = 2) is quite different from that of CO(v = 17).…”

“…Here the mean final translational energy of the scattered molecules is shown as function of the thickness of the Ag-layers on the Au (111) surface [39]. The mean final energy does not change when the layer thickness is larger than 4 ML.…”