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Surface chemistry of iodine on platinum (111)

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dc.contributor.author Furman, Scott Anthony
dc.date.accessioned 2017-09-11T20:37:24Z
dc.date.available 2017-09-11T20:37:24Z
dc.date.copyright 1998 en_US
dc.date.issued 2017-09-11
dc.identifier.uri https://dspace.library.uvic.ca//handle/1828/8556
dc.description.abstract The adsorption of iodine on a platinum(111) single-crystal surface has been investigated using LEED, Auger spectroscopy, and work function measurements. The phase transformations and work function changes have also been measured during desorption. Mass spectroscopy shows that above 300 K the main desorption product is atomic iodine with a small amount of molecular iodine detected as well. The desorption kinetics at these temperatures were studied by different techniques to extract the kinetic parameters and the orders of the desorption reactions. There are two main desorption features, one displaying zero-order desorption kinetics typical of a phase transition and the other displaying first-order kinetics with a coverage-dependent activation energy. The work function changes during adsorption and desorption were shown to be a function of coverage rather than having a site dependence. The adsorption of iodine at temperatures below 200 K was also studied. Multilayers of molecular iodine are formed that desorb with essentially zeroth order kinetics. Two multilayer desorptions were observed with thermal desorption spectroscopy. One of the multilayer desorptions had a significant work function change associated with it. The work function changes were modelled by calculating the hybridization dipole moment using extended-Hückel theory with Bloch wavefunctions. The calculations are sensitive to the atomic position of the adsorbate and require further refinement. Due to the protective nature of the iodine layer and its high polarizability, the iodine layers were used to study the ambient pressure adsorption of fluorinated carbosilane dendrimers. These dendrimers are stable in vacuum but do not form an ordered structure at ambient temperature. Heating the adsorbed dendrimer in vacuum to 1100 K produced a new ordered structure on the platinum surface. This structure was shown not to be an intact dendrimer molecule as two different dendrimers with similar structural moieties produced the same (√19x√19)R23.4° LEED pattern. The ordered structure was studied by Auger spectroscopy to determine the carbon coverage. This structure is proposed to be islands of a coincidental lattice of graphite. en_US
dc.language English eng
dc.language.iso en en_US
dc.rights Available to the World Wide Web en_US
dc.subject Surface chemistry en_US
dc.subject Iodine en_US
dc.subject Platinum en_US
dc.title Surface chemistry of iodine on platinum (111) en_US
dc.type Thesis en_US
dc.contributor.supervisor Harrington, David A.
dc.degree.department Department of Chemistry en_US
dc.degree.level Doctor of Philosophy Ph.D. en_US
dc.description.scholarlevel Graduate en_US


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