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Title: Some surface properties of silver and gold
Author: Hart, C. G.
ISNI:       0000 0001 3540 6746
Awarding Body: University of London
Current Institution: University College London (University of London)
Date of Award: 1974
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Clean silver and gold surfaces were prepared under ultra high vacuum by the deposition of films of the metals onto pyrex or B37 glass substrates. The adsorption of hydrogen, xenon and carbon monoxide was studied on these films. Measurements of surface potential, equilibrium pressure and rates of adsorption were made as a function of coverage of the surface by the adsorbate. Certain of the properties of the. films towards these gases were found to be dependent on the choice of glass substrate. Xenon surface potentials of 48OmV for silver and 470mV for gold were recorded, and the form of the surface potential vs coverage curves discussed in terms of some simple models. The occurrence of a phase change near the half monolayer is postulated for this system. Surface potential data for carbon monoxide included maximum values of 460mV on silver and 660mV on gold, and for hydrogen included maximum values of -320mV on Ag/pyrex and -265mV on Ag/B37: on gold the surface potential reached a maximum value of -100mV near half coverage and subsequently fell to near -70mV at full coverage. Surface potential and adsorption rate data indicated the occurrence of interactions between hydrogen atoms and xenon or carbon monoxide pre-adsorbed on these surfaces. Some features of these are discussed in terms of a simple hydrogen atom recombination model. The reported desorption of hydrogen on adding xenon to a hydrogen covered surface is also implicit in this model.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available