The usual virial theorem, relating kinetic and potential energy, is extended to a molecule by the use of the true wave function. The virial theorem is also obtained for a molecule from a trial wave function which is scaled separately for electronic and nuclear coordinates.

M.Sc. / Please refer to full text to view abstract

Bismuth(III) has been used in the medicinal industry for many years, but its mechanism of action is not fully understood and there is very little information on thermodynamic and kinetic parameters for complex formation. Amino acids are the building blocks of life and so, by initially simply determining the complexing ability of various amino acids with bismuth, an indication of how bismuth could interact in the body can slowly be developed and could assist in the eventual development and design of more effective bismuth containing drugs.

Liao, Zhenwu. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 86-91). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.

The decay rates for molecules at rough surfaces are studied via an island surface model, with particular emphasis on the effect due to the distribution of surface roughness. Two extreme cases are studied when the surface islands distribute themselves evenly and when they coalesce to form local clusters at the molecule-substrate interface. The optical properties of the interfacial layer in these two cases are described by the Maxwell-Garnett and the fractal-cluster models, respectively. Among other results, it is found that both enhancement and suppression of the surface-induced decay rates are possible due to the presence of roughness, with more dramatic suppression taking place when the surface islands coalesce to form clusters.

Amphipathic molecules are basically long chains, one end of which likes water (is hydrophilic) and the other end abhors it (is hydrophobic). These molecules tend to sit vertically in a fluid and adhere to each other. This attraction of adjacent molecules causes the molecules to condense into regions, referred to as polymer Langmuir layer domains, which are a single molecule thick and behave like a two dimensional fluid. This attraction also manifests itself as a line tension, analogous to surface tension in a fluid droplet, which causes the regions to become circular as they attempt to minimize the length of their perimeter. Often the layer will form holes, gaps in the liquid monolayer which contain a much smaller density of molecules. In the presence of humidity, the holes are observed to close up, pulled together by the line tension as well as condensation of the hole molecules at the boundary. Previous researchers have computed the fluid velocity for the process when the hole is assumed to be a vacuum. I, however, propose to replace this model with a gas, adding condensation of gas from the hole into the liquid domain of the monolayer to the line tension force. The hope is to obtain a mathematical model that better corresponds to the physical problem than current models do.

1 / Xiaoye Su

Luminescent properties of the dye molecules can be influenced by the environments as well as intermolecular interactions. Suitable control the aggregation can be useful for optoelectronic device applications. In this thesis, we investigate the spectroscopic properties of dye molecule, DiI_C18, in solutions. Solvents and concentrations are used to control the degree of aggregation. Absorption and emission are used to probe the properties. We use water, methanol, and ethylene glycol as key solvents to control the aggregation effects, especially the methanol solution mixing with water. As the concentration increased, the change of the absorption spectra are observed, which is caused by the aggregation between molecules. Two types of aggregations: head-to-tail structure and parallel structure, are proposed. Head-to-tail structure behaves red-shifted spectrum, and a corresponding shorter decay lifetime. On the contrary, parallel structure aggregation exhibits blue-shifted absorption spectrum and a longer fluorescence lifetime. Both structures are observed at different period after mixing. Only monomer exists in the methanol solution, even at high concentration. However, after missing with water, parallel structure aggregates are formed. Head-to-tail structure aggregates are formed after a much longer period, usually several hours after the mixing. These aggregates not only have different photo-physical properties. After high light intensity illumination, parallel structures are easier to turn into non-fluorescent structures, while head-to-tail structures last a longer period. Monomer structures exhibit the longest period. This provides additional evidence for the formation of different structures in the mixing solutions.

Thesis (M.D. Sc.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 91-100). Available also in a digital version from Dissertation Abstracts.