The University of Southampton
University of Southampton Institutional Repository

The adsorption of monolayer films of Uranium and Zirconium on Tungsten

The adsorption of monolayer films of Uranium and Zirconium on Tungsten
The adsorption of monolayer films of Uranium and Zirconium on Tungsten
The form and magnitude of the potential change at the surface of a metal is of paramount importance in electron and atom interactions in this region. The theoretical activity in the study of these surface potentials has increased in recent years, stimulated mainly by the plethora of data now available as well as the upsurge in the technological applications of surface phenomena. However there has been a need for a few accurate measurements of the dependence of the surface potential, that is the variation in work function, on the condition of well-defined surfaces. This thesis not only fills this gap but assesses the many phenomenological theories presently available. New lines of enquiry, both in the development of these theories and in the form of future experiments capable of unambiguous interpretation, are suggested. The change in work function on adsorption of uranium and zirconium on single crystal and polycrystal tungsten surfaces has been exhaustively investigated, the measurement technique being, for the most part, the Zisman vibrating capacitor modification of the Kelvin method. The majority of the work concerned films of up to one atomic layer, evaporated on to (110) and (100) oriented tungsten crystals, The use of ultra-high vacuum techniques, essential to the achievement of the extreme cleanliness required for this work, is described in some detail. Pressures of below 1 x 10 torr were routinely obtained, and allowed measurements to be made on surfaces that were atomically clean. The way in which the work function was affected through contamination by residual gases has also been studied. In the course of this work a relationship was established which enabled the work function change due to adsorption of a wide range of materials to be predicted. For each orientation of the tungsten substrate a unique number exists which, together with the adsorbate electronegativity, makes this calculation possible. The relevant adsorption theories concerning work function changes in bimetallic adsorption systems are discussed and assessed. Despite recent activity in fundamental many-body concepts no theory is yet sufficiently developed to allow comparison with experiments. It is concluded that even the phenomenological theories reviewed in this work cannot as yet adequately predict work function/coverage data.
University of Southampton
Sargood, Adrian
96d07811-2092-4839-ad30-ee18737ef656
Sargood, Adrian
96d07811-2092-4839-ad30-ee18737ef656
Hopkins, B.J.
25506e65-1055-429d-8ac7-f2091da9f651

Sargood, Adrian (1969) The adsorption of monolayer films of Uranium and Zirconium on Tungsten. University of Southampton, Doctoral Thesis, 337pp.

Record type: Thesis (Doctoral)

Abstract

The form and magnitude of the potential change at the surface of a metal is of paramount importance in electron and atom interactions in this region. The theoretical activity in the study of these surface potentials has increased in recent years, stimulated mainly by the plethora of data now available as well as the upsurge in the technological applications of surface phenomena. However there has been a need for a few accurate measurements of the dependence of the surface potential, that is the variation in work function, on the condition of well-defined surfaces. This thesis not only fills this gap but assesses the many phenomenological theories presently available. New lines of enquiry, both in the development of these theories and in the form of future experiments capable of unambiguous interpretation, are suggested. The change in work function on adsorption of uranium and zirconium on single crystal and polycrystal tungsten surfaces has been exhaustively investigated, the measurement technique being, for the most part, the Zisman vibrating capacitor modification of the Kelvin method. The majority of the work concerned films of up to one atomic layer, evaporated on to (110) and (100) oriented tungsten crystals, The use of ultra-high vacuum techniques, essential to the achievement of the extreme cleanliness required for this work, is described in some detail. Pressures of below 1 x 10 torr were routinely obtained, and allowed measurements to be made on surfaces that were atomically clean. The way in which the work function was affected through contamination by residual gases has also been studied. In the course of this work a relationship was established which enabled the work function change due to adsorption of a wide range of materials to be predicted. For each orientation of the tungsten substrate a unique number exists which, together with the adsorbate electronegativity, makes this calculation possible. The relevant adsorption theories concerning work function changes in bimetallic adsorption systems are discussed and assessed. Despite recent activity in fundamental many-body concepts no theory is yet sufficiently developed to allow comparison with experiments. It is concluded that even the phenomenological theories reviewed in this work cannot as yet adequately predict work function/coverage data.

Text
Sargood - Version of Record
Available under License University of Southampton Thesis Licence.
Download (36MB)

More information

Published date: 1 January 1969

Identifiers

Local EPrints ID: 437794
URI: http://eprints.soton.ac.uk/id/eprint/437794
PURE UUID: 0bdb109d-a89b-444e-a649-33bcef1bc32c

Catalogue record

Date deposited: 17 Feb 2020 17:31
Last modified: 05 Jun 2020 16:32

Export record

Contributors

Author: Adrian Sargood
Thesis advisor: B.J. Hopkins

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×