The Reactivity and Structure of Solid Surfaces, Phase II.
Final rept. 1 Nov 71-31 Jul 75,
CALIFORNIA UNIV BERKELEY DEPT OF CHEMICAL ENGINEERING
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Atomic and molecular beam scattering has been used along with LEED, Auger spectroscopy, and temperature programmed-desorption to study the structure of silver, platinum, tungsten, and iridium surfaces, and the interaction of helium, neon, argon, krypton, xenon, oxygen, hydrogen, methane, nitrogen, and carbon monoxide with these metal surfaces. Scattering of the rare gases displayed non-diffractive, quasi-elastic scattering for HeAg111, inelastic scattering for Ne, Ar, KrAg111, and trapping-dominated scattering for XeAg111. Rare gas scattering of HeW112 gave quasi-elastic diffraction, NeW112 gave inelastic rainbow scattering, and Ar, Kr, XeW112 gave trapping-dominated scattering. The quasi-elastic helium diffraction has been represented well by semi-classical theory which can be extended to other surface scattering problems, including LEED. Scattering of polyatomic molecules has shown, that except for the hydrogenic molecules, rotational coupling is very weak compared to translational coupling. Adsorbed oxygen on Pt111 results in a 2x2 LEED pattern but the surface mesh of the Pt110 is unchanged for the adsorption at low temperatures in the reactive state. This surface chemistry on the single crystal plane is sufficient to explain quantitatively the oxygenation of carbon monoxide in a commercial catalytic muffler.
- Physical Chemistry