Although many multi-component polymer systems are well characterised, the surface properties of polymers mixed with low surface energy additives have received little attention. In addition, the new branches of scanning probe microscopy that enable high resolution mapping and modification of surface charge distributions have been infrequently applied to polymer surfaces. The surface segregation of a fluorochemical additive directly from a polypropylene host matrix has been investigated by AFM and other surface analysis techniques. The level of surface enrichment was found to be governed by the temperature and duration of annealing. Further investigation revealed that the speed and extent of surface enrichment of the additive increases with polymer molecular weight. The effect of additive structure on surface segregation has also reported. A method of depositing charge onto polypropylene substrates from a high potential scanning AFM tip was developed. The relation between AFM tip- voltage and the level of charge deposited on the substrate suggested that a localised corona discharge was generated. AFM scanning parameters were found to effect the deposition of charge. The charging behavior of fluorochemical doped polypropylene surfaces was investigated on macroscopic scales using a scanning electrometer probe, and on microscopic scales using EFM. Fluorochemical domains at the surface have been found to preferentially accumulate both positive and negative charge. Surface charge distributions were found to become more uniform during annealing. Sub-micron particle capture by charged surfaces was investigated using EFM. In addition, spatially confined amine beads were deposited onto a patch of localised charge and subsequently functionalised to produce a metallic gold coating.

<p> Atomic resonances present a difficult chapter in the study of atomic structure. The calculation and measurement of these resonant states have provided a challenge for both theorists and experimentalists. This work focuses on the numerical calculation of the resonant states. Some years ago a method to calculate the resonant states of three-body atomic interactions was developed. This method involves solving the Faddeev equations using a Merkuriev cut and a Coulomb-Sturmian basis, and will be the method used for the calculations in this work. This method was used as an alternative to the more conventional methods of calculating atomic resonant states. At the time of its derivation, the method was used to calculate the narrow-width resonances of the electron-Positronium (e &ndash; Ps) system, which showed accurate results with respect to the calculations done by other groups using alternative methods. Additionally, the method saw an emergence of resonances (broad-width) which line-up to the system thresholds. We have come to call these broad-width resonances the threshold resonances. However, at the time, these threshold resonances proved too computationally intensive to make confident results. Now, with the assistance of better computational resources and an improved code, this problem is again addressed. </p><p> New calculations of the narrow-width and threshold resonances were completed which support the appearance of the threshold resonances in the e &ndash; Ps system. The threshold resonances were observed lining up at the first, second, and third two-body thresholds, a trend that is assumed to continue at even higher energies. Calculations were carried out for both the 1S and 3S states. After successfully making calculations of the e &ndash; Ps system resonant states, calculations were also carried out for the electron-Hydrogen (e&ndash;H) 1S and 3S resonances. The calculations for the e &ndash; H system were carried out for the threshold resonances emerging from the 1st threshold. Additionally, we propose an explanation for the emergence of the threshold resonances.</p>

No description available.

Calculations have been carried out in the distorted-wave Born approximation for electron-impact excitation of the individual 2p fine-structure states of the hydrogen atom. Results are given for 54.4, 100, and 200 eV. The purpose was not to improve on existing more elaborate calculations of the state multipoles of the excited 2p states, but rather to investigate spin-related phenomena, such as an incident polarized beam, polarized target atoms, and the polarization of the scattered electrons when unpolarized electrons are incident on unpolarized target atoms. The bound state wave functions are constructed using the total angular momentum scheme, $\vert JM\sb{J}\rangle = \sum\limits\sb{M\sb{L}M\sb{S}}C(LSJ;M\sb{L}M\sb{S}M\sb{J})\vert LM\sb{L}SM\sb{S}\rangle$, and the Percival-Seaton hypothesis is not used. We then construct explicitly-spin-dependent scattering amplitudes. This approach is to be contrasted with previous calculations which use $\vert LM\sb{L}SM\sb{S}\rangle$ wave functions and assume that the sum of the electron spin projections is conserved in the collision, or with calculations which use uncoupled wave functions. / The spin polarization of the scattered electrons resulting from scattering unpolarized electrons on unpolarized ground state hydrogen atoms (the 'fine-structure effect') is found to result here from interference of the direct and exchange scattering amplitudes. Distortion of the scattered waves by the atomic potential produces a nonzero component of the transferred angular momentum perpendicular to the scattering plane. This orbital angular momentum orientation of the excited atom is then transferred to the scattered electron via angular momentum algebra. The spin-orbit interaction in the excited atom is the origin of the spin polarization, since it produces a sufficient energy separation of the fine structure states to allow them to be studied separately. / Source: Dissertation Abstracts International, Volume: 56-04, Section: B, page: 2085. / Major Professor: W. N. Shelton. / Thesis (Ph.D.)--The Florida State University, 1995.

Tsui Shu Ki. / Bibliography: leaves 110-112 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1985

Digitized by Kansas Correctional Industries

Total cross sections for charge transfer and electron detachment for collisions of a variety of negative ions with atomic hydrogen have been separately determined for laboratory collision energies ranging from about 5 eV to 500 eV. The experiments are performed with an apparatus that utilizes a crossed-beam configuration with a radio-frequency discharge as the source of atomic hydrogen.;For collisions of H{dollar}\sp-{dollar}(D{dollar}\sp-{dollar}) with H the charge transfer cross sections increase monotonically with decreasing energy and display an isotope effect. at the lowest collision energies, the electron detachment cross sections are about one order of magnitude smaller than those for charge transfer; for the two projectiles the detachment cross sections are identical when compared at the same relative collision energy.;Total electron detachment cross sections have also been measured for collisions of Halogen anions with atomic hydrogen. For F{dollar}\sp-{dollar}, Cl{dollar}\sp-{dollar}, and Br{dollar}\sp-{dollar} projectiles the measured detachment cross sections increase with decreasing collision energy, and no energetic threshold is indicated; no charge transfer is observed. For I{dollar}\sp-{dollar} + H, however, the detachment cross sections are small at low collision energies, and increase rapidly with increasing energy. HI{dollar}\sp-{dollar} is known to form a stable molecular anion, and a small charge transfer cross section is measured to be less than 1 A{dollar}\sp2{dollar} at the highest collision energy.;For collisions of O{dollar}\sp-{dollar} and S{dollar}\sp-{dollar} with atomic hydrogen, electron detachment is also found to be the dominant electron loss mechanism, and the measured total detachment cross sections are found to increase with decreasing collision energy. For both projectiles, charge transfer cross sections are measured to be small and energetic thresholds are indicated.;The experimental results are compared with several calculations and previous measurements that overlap the present results at the highest energies, and are discussed, where possible, in terms of various intermolecular potentials which have been calculated previously.

No description available.

No description available.

No description available.