The interaction between high-n Rydberg states of molecular hydrogen and metal surfaces has been investigated for the first time. Rydberg states of hydrogen possessing either 0 or 2 units of rotational angular momentum, defined by the quantum number N⁺ , and principal quantum numbers in the range n= 17 22 (for the N⁺= 2 states) and n=41-45 (for the N⁺= 0 states) are directed at a grazing angle onto a metal surface (gold or aluminium). At a sufficiently close distance ionisation may occur via tunnelling of the Rydberg electron into the vacant metal conduction band. Any ions formed in the vicinity of the metal are extracted by the application of an electric field and information about the distance at which the ions are formed can be inferred from the magnitude of the applied field required for detection. Two novel effects are observed. Firstly, it appears that the rotation of the H2⁺ core has a significant effect on the ionisation properties of the Rydberg states in a manner akin to rotational autoionisation, such that the rotational energy of the core is given up to the Rydberg electron. Secondly, the surface ionisation profiles do not vary smoothly with applied field suggesting that at certain fields the feasibility of ionisation is either enhanced or reduced. A preliminary discussion of the origin of the structure is presented in terms of the crossings in the Stark map between the N⁺= 0 and N⁺= 2 Stark manifolds. The development of a theoretical model, and an associated Fortran program, involving the technique of complex scaling is also reported. The hydrogen molecules are modeled using an atomic hydrogen system which provides a good first approximation to the behaviour of the Rydberg electron for states with n > 5. Energies and linewidths, for states with principal quantum number n= 6 9 interacting with a model surface, are explicitly calculated at a range of surface separations. From this information, predictions of the ionisation behaviour expected for states of higher principal quantum number are presented.

Diamond is of interest as an advanced functional material, since the extreme physical properties of diamond, suggests it is ideally suited to a range of new demanding applications. In this context, the thesis explores basic surface chemical properties of diamond thin films, along with electrochemical, electronic and electron emission processes involving this material. New experiments are reported concerning the nature of surface conductivity on diamond. Measurements clearly show that the conductivity only arises if a hydrogenated diamond surface is exposed to water vapour, in the presence of chemical species capable of acting as electron acceptors. The conduction properties of surface conductive diamond in aqueous solution are also studied, and the first detailed electrochemical investigations of this material are described. Comparative electrochemical studies of nanocrystalline and boron-doped diamond have been performed. Investigations of electrode stability, and the accessible "potential window" are described, as well as the behaviour of a range of 'redox' systems, including transition metal complexes, metal deposition/stripping, and bio-related organic species. Significant differences between the behaviour of nanodiamond and microcrystalline boron-doped material are observed. A range of surface chemical and threshold photoemission studies of diamond thin films are reported. The results indicate that quantum photoyields (QPYs) are insensitive to the diamond "quality", although the wavelength selectivity is dependent on it. The adsorption of oxygen strongly reduces the QPY, although this only occurs slowly in the presence of O₂ because of a low reactive sticking probability. Much more rapid uptake of oxygen and consequent reduction of photoyield is observed in the presence of atomic O or electronically excited dioxygen O₂*. The presence of alkali metals on the diamond surface increases the QPY, and reduces the sensitivity of the QPY to surface oxygen. Significant differences between the surface chemical properties of Li, and other adsorbed akali metals (K and Cs) are observed.

The work in this thesis is primarily aimed at supporting the NBe (Nuclear, Biological and Chemical) aspect of Crusader 21, the military clothing programme for the early 21st Century. This aims to produce a multi-purpose, systems-orientated combat ensemble for the UK Armed Services. Conventional "wet" techniques for chemically modifying fabrics have certain disadvantages, however employing plasma technology may provide a route for many novel "multi-functional effects" fabrics such as repellency against toxic chemical agents. In order to produce repellent coatings the surface must have a low surface energy. To obtain this, inert chemical groups need to be attached to the solid substrate. In addition to chemistry, surface roughness plays an important role in repellency. Liquid repellent surfaces have been produced by the pulsed plasma polymerisation of I H, 1 H,2H,2H -heptadecafluorodecyl acrylate. These films have chemical functionalities indicative of polymerisation occurring through the acrylate double bond, as shown by Infrared Spectroscopy analysis. Structural retention was optimised using experimental design techniques and resulted in a critical surface tension of wetting as low as 4.3 mN m-I (c.f. Teflon 18.5 mN m-I). Plasma deposition of a functionalised surface followed by reaction with a fluorinated alcohol proved less affective. Enhanced deposition rates for 1 H, 1 H,2H-perfluorododec-I-ene, over the saturated analogue, have indicated that polymerisation can occur during the off-time of the pulsed plasma period, via free radical polymerisation pathways. X-ray Photoelectron Spectroscopy (XPS) has indicated greater structural group retention for monomers containing double bonds. In order to obtain super liquid repellency the effect of surface roughness was investigated, where both commercially available rough surfaces and plasma roughened substrates were utilised. Once optimised, the rough surfaces were coated with 1 H, 1 H,2H,2H-heptadecafluorodecyl acrylate and produced super repellent films.

No description available.

No description available.

No description available.

This thesis is concerned with the experimental determination of surface displacements of material foils by means of an automatic evaluation of the holographic interferograms obtained in testing. The experimental work utilizes a newly developed method referred to as the "holographic-electro-optical" technique that employs a specially designed microcomputer unit. The experimental procedure and the microcomputer organization are fully described. The application of this technique is illustrated by the evaluation of strain field and thickness changes at a large number of points on both sides of a commercial newsprint paper sample subjected to uniaxial loads. Furthermore, a new quantity called the "volumetric mass density" is introduced for this material for the first time that is experimentally evaluated and correlated to the obtained strain field. In the conclusion of this thesis general remarks concerning the holographic-electro-optical technique are given and the obtained results for the newsprint sample and future research are indicated.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1990. / Includes bibliographical references (leaves 118-122) / Microfiche. / xv, 122 leaves, bound ill. 29 cm

Thesis (PhDBiomedicalScience)--University of South Australia, 2001.

Thesis (PhD)--University of South Australia, 1997