A molecular beam study of the NO interaction with Pt(111)

Abstract

Using angle and time resolved molecular beam techniques, an investigation of the low coverage adsorptiondesorption kinetics of NO on Pt(l!!) is made. The experiments are carried out over a crystal temperature range of 300 K < T, < 900 K. For T, > 500 K, the sticking probability s > 0.9. NO adsorbs molecularly with little dissociation « 5%). The desorption rate is found to be strongly dependent on the incident beam flux and trace amounts of chemisorbed oxygen « 1%) on the surface. These findings suggest that steps play the dominant role in low coverage kinetics for a nominally flat crystal. We present a model which incorporates the effect of steps, explains the nonlinearity of the desorption kinetics, and reconciles the disagreement between these results and previous molecular beam studies.

Vibrational excitation and deexcitation rates of molecules adsorbed on metal surfaces

“…fast desorption rates) at which these experiments were performed. Under -these conditions' the molecules on the surface desorb from terraces rather than from steps or--defects as was argued to occur at lower temperatures [15]. In Ref.…”

Studying transient mobility and energy loss using scanning tunneling microscopy

“…This importance is largely due to the special and often dominant chemical roles played by special surface sites such as steps and defects [ 1,2]. It is motion to and reaction at these sites which are thought to determine many surface reaction rates [ 1,2].…”

“…The processes by which adsorbates move across surfaces are important in such diverse areas as catalysis, film growth, semiconductor device fabrication, surface processing, wetting, corrosion, and etching [1][2][3][4]. This importance is largely due to the special and often dominant chemical roles played by special surface sites such as steps and defects [ 1,2].…”

“…This importance is largely due to the special and often dominant chemical roles played by special surface sites such as steps and defects [ 1,2]. It is motion to and reaction at these sites which are thought to determine many surface reaction rates [ 1,2]. While many measurements have been made of surface diffusion [5][6][7][8], the motion due to adsorbate momentum parallel to the surface upon adsorption or due to exothermic surface processes has received much less attention [9][10][11][12][13][14].…”

Generation of ultra-short hydrogen atom pulses by bunch-compression photolysis

“…See for example, ref. 12), time-resolved studies of surface adsorbate equilibration 13 as well as real-time kinetics of thermal desorption from terraces and steps 14,15 . Synchronized scattering of ultra-short matter pulses from photo-excited surfaces is another opportunity.…”