Brief history of precursor-mediated chemisorption for facile systems

BRIEF HISTORY OF PRECURSOR-MEDIATED CHEMISORPTION FOR FACILE SYSTEMS 

A fair amount of research has been conducted on so called facile precursor-mediated chemisorption systems. The section that follows is a review of selected existing studies and will serve as a useful introduction to these gas-surface dynamics and will provide a foundation for later discussions of activated chemisorption systems. 

Previous studies of the scattering of Xe from the Pt( 1 1 1) surface has contributed much in understanding the chemistry and important parameters governing adsorption and desorption from metal surfaces. 

Hurst and co-workers [24] used time-of-flight (TOF) spectra to study the scattering of Xe from a clean Pt(l 1 1) surface. This group obtained TOF spectra containing two distinct peak features. An example of some these spectra are shown in Fig. 3. 

Hurst et al. attributed the second of these spectral peaks (the peak occurring at later times) to Xe atoms which had accommodated to the surface (i.e. come into equilibrium with the surface at a surface temperature of Ts) and subsequently desorbed from the surface. The other peak present in the spectra was attributed to Xe atoms that had directly scattered, without thermal accommodation, from the surface. 

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