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Title:A new approach to the study of surface phenomena, measurements of diffusion rates, intermolecular distances and electronic properties of CO chemisorbed on supported platinum catalysts by nuclear magnetic resonance
Author(s):Ansermet, Jean-Philippe
Doctoral Committee Chair(s):Slichter, C.P.
Department / Program:Physics
Subject(s):surface phenomena
diffusion rates
intermolecular distances
electronic properties
CO chemisorbed
supported platinum catalysts
Nuclear magnetic resonance (NMR)
transverse relaxation
Abstract:The author has applied magnetic resonance to study the chemisorption of CO on supported platinum particles. The particles are 10 to 50 Ansgtrom in diameter, supported on alumina. CO is 90% enriched with 13CO. NMR data were taken from 4 K to 600 K. He shows that a measurement of transverse relaxation at 77 K can be used to measure relative distances among molecules in the adsorbed layer. His measurements of transverse relaxation and of spin-lattice relaxation are consistent with the geometry of CO layers chemisorbed on single crystal surfaces. He has observed the narrowing of the NMR line and the effects of motion on transverse relaxation from 300 K to 600 K from which he deduces diffusion energies of 13 and 16 plus/minus 2 kcal/mol, in agreement with measurements of R. Lewis and R. Gomer of the diffusion of CO on Pt tips by Field Emission Microscopy. He demonstrates that conduction electrons are present on CO and shows that the distribution of spin-lattice relaxation times observed at 77 K reflects the various binding configurations present at the surface of each particle, irrespective of the particle size.
Issue Date:1985
Genre:Dissertation / Thesis
Rights Information:1985 Jean-Philippe Ansermet
Date Available in IDEALS:2011-06-06
Identifier in Online Catalog:862800

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