The quantum mechanical investigation of molecular dimers, trimers and, to a greater extent, higher clusters, constitutes a legitimate attempt towards linking the gas and condensed phases of matter. The interaction of gas-phase clusters with ionizing media can result in anion formation, a special class of which, the dipole-bound anions is the main focus of this dissertation. By applying special techniques of ab initio calculations to model systems, we have addressed the question of the extent to which certain molecular species can form dipole-bound anions. We have shown the effects of attaching a dipole-bound electron on charge distribution, geometrical distortions, and mechanistic fates of certain reactive clusters. Our investigations include cases of homodimer anions where we reported the feasibility of formation of a dipole-bound anion for the dimer agglomerates to the exclusion of the single molecules (ethylene glycol and hydrogen fluoride). The hydrogen cyanide-water anion is a heterodimer system where our results demonstrate the effect of linkage isomerism on an isomer's ability to form dipole-bound states. Only the [H₂O...HCN]⁻ anion was experimentally detected and it corresponds to the higher EA we reported. In addition, the formation of meta-stable trimer and tetramer dipole-bound anions in the water cluster system is supported by our calculation. The water cluster study demonstrates the utility of ab initio calculation techniques for investigations of reaction mechanisms in the gas phase. For instance, both the mass spectrum intensity pattern and general mechanism of formation of the cluster anions can be inferred from the relative stabilities and geometries that we obtained for the anion and neutral systems. Finally, we point out the potential utility of an IR analysis in distinguishing neutral from anion systems, based on shifts of certain IR bands generated in our harmonic frequency analysis. We hope that our results for electron affinities, dipole moments, and vertical detachment energies will serve as a useful resource for the researchers in the field. In conjunction with the corresponding values measured by experimentalists, both results should provide a self-consistent system for identifying and overcoming shortcomings of both experimental and theoretical approaches of solving chemical and physical problems involving anion formation.

Termolecular association reactions were studied at the low temperatures produced within the core of a free jet expansion. A strong inverse temperature dependence was found in the termolecular association rate coefficients for the reactions of NO⁺ with NO and N₂ and the results are compared with existing literature and theories. The atmospheric ramifications of the reaction NO⁺ + 2 N₂ are discussed. The temperature dependence of the termolecular association reaction of H⁺ + 2 H₂ is reported for the range 1.6-3 Kelvin and a temperature dependent rate coefficient for the range 1.6-300 Kelvin is reported using the current results and the available high temperature literature. Measurement of the autoneutralization lifetime of SF₆⁻* formed by the attachment of low energy (1-100 meV) electrons to cold SF₆ molecules within the core of a free jet expansion were made. The excited anions were found to exhibit a single lifetime in accordance with the s-wave scattering law and with literature values for the temperature dependence of both the electron attachment rate coefficient and excited anion lifetime. These studies provide insight into the attachment/detachment dynamics of negative ion scattering states under single collision conditions. The effect of neutral temperature on termolecular association reactions is examined for several chemical systems and discussed within the context of models which include the formation of a long-lived collision complex.

Several new techniques were developed and applied to investigate various non-trivial aspects of vibrational motion. In particular, a novel strategy for accurate determination of vibrational energy levels in the presence of intramolecular hydrogen bonds was proposed. A small subset of convenient internal coordinates was chosen to represent a vibrational mode of interest, while the interdependence among all other coordinates was encoded in the g-matrix elements which appear in the kinetic energy operator. Individual g-matrix elements were modeled by series of shifted Gaussian functions, a newly proposed functional form that assured physically correct behavior for the entire domain of internal coordinates. The success in reproducing experimentally observed frequencies should be partly attributed to a new basis set of modified Hermite-type functions which has been introduced in this work and employed in all presented vibrational energy calculations. A novel functional representation for potential energy surfaces (PES) was also proposed in this work. The new representation, consisting of products of shifted Gaussians and shifted Morse functions, reproduces all local features near the bottom of the well and also possesses correct asympototic behavior. Determination of the functional parameters for the PES fits involved a simultaneous optimization of many linear and nonlinear parameters, and required a development of an efficient minimization routine. The new routine consisted of an iterative procedure, which treated sets of linear and nonlinear parameters separately and in successive order in each iteration. The above-mentioned set of developed tools was applied to study the intramolecular vibrational energy redistribution (IVR) in HDO molecule. The time-evolution of the O-H stretching local mode was studied by a time-propagation method based on matrix representation of the evolution operator. The energy transfer among the local modes was modeled by non-diagonal g-tensor terms in the kinetic energy operator and by three-dimensional potential energy operator. The results indicate that the O-H stretching local modes must be substantially long-lived within the chosen model. A new recursive programming technique combined with a very effective passing by reference methodology was developed and used in this study to implement the time-propagation routine. The introduced concept of a shared compound pointer in Fortran 90 automatically accounts for the changing sizes of all data structures, while working with only a single parameter, a pointer to a parent object.

To maintain its innovative and competitive edge the forestry sector is focused on conducting research into more efficient ways of manufacturing current products and generating new markets for by-products and technologies. It is the surface of pulp fibres which are of fundamental importance to the pulp and paper industry. A better understanding of the chemistry and morphology of Kraft pulp fibres is the primary motivation for this Master's thesis study. Through this work, we will show that simple and straight applications of newer technologies (X-ray photoelectron spectroscopy, Atomic Force microscopy, Optical Microscopy and Differential Scanning Calorimetry) could be employed by the pulp and paper industry to determine the surface chemistry of Kraft Pulp fibres (and therefore other lignocellulosic fibres). The effect that variability in the surface composition of such fibres has on industrial applications is commented on. / Pour maintenir son avantage innovateur et concurrentiel, le secteur de sylviculture est concentré sur la recherché dans des manières plus efficaces de produire des produits et des marchés courants pour des sous-produits et des technologies. C'est l'extérieure des fibres de pâte qui est d'importance fondamentale pour l'industrie de pâte et papier. Une meilleure compréhension de la chimie et de la morphologie des fibres de pâte Kraft est le raisonnement primaire pour cette thèse de maîtrise. Dons çe recherche nous démontrons que des applications simple et directes de nouvelles technologies (spectroscopie de photoélectron de rayon X, microscopie atomique de force, microscopie optique, analyse entalbique différentiel) peuvent être utilisés par l'industrie de pâte et papier pour déterminer la composition extérieure des fibres de pâte Kraft (et donc d'autre fibres lignocellulosique.) L'effect de la variabilité en composition extérieure sur des applications industrielles sera aussi étudié.

The binding of aqueous solutions of sodium cholate and chenodeoxycholate with a lightly cross-linked polyacrylamide resin carrying N,N,N-trimethylammonium dodecyl chloride pendants (QPDA12) have been studied by HPLC data under various conditions. The goal of this thesis was to determine the relative enthalpic and entropic contributions to the binding that would aid in establishing the molecular basis of the process and in the development of effective resins that sequester bile salts. / The binding constants were extracted from the fit of the isotherms to the Langmuir equation and their temperature dependence was employed to evaluate the thermodynamic parameters associated with the process. The binding was endothermic and entropy-driven. Stronger binding was always associated with a higher enthalpy barrier. Enthalpy-entropy compensation was observed encompassing data for both cholate and chenodeoxycholate binding under the influence of a variety of perturbations to the solvent. A compensation temperature of 293 K was obtained, which is characteristic of processes in which water plays a central role. The parameters observed were used to rule out earlier molecular descriptions of the process, and an alternate mechanism was proposed that emphasised the significant role of hydrophobic hydration changes in the sequestering of the bile salts. / The temperature dependence studies were extended to the binding of sodium cholate with a lightly cross-linked hydrophilic resin possessing lysine-containing peptide pendant groups. In sharp contrast with the Langmuir behaviour of the isotherms found with the QPDA12 resin the binding behaviour with the peptide resin was of a complex nature. There was a very distinct sigmoidal feature in the binding process, which is the signature of cooperative binding. A weaker binding manifested itself in the latter half of the binding isotherms. An analysis of the temperature dependence revealed that the binding was exothermic throughout the isotherm. However, while the initial weak binding was in part entropy-driven, the subsequent stronger cooperative interactions resulted in binding that was associated with negative entropy changes.

The knowledge of how cells interact with man-made materials is crucial for the design of specialized biomaterials. These interactions are mainly based on the physical properties of that material. In order to study the effect of these properties, polyelectrolyte multilayers were used: these are coatings able to mask any material, which are carefully built from the bottom up using the layer-by-layer technique. The biologically relevant physical properties of these coatings are tuneable by altering conditions of their build up, such as the pH and/or salt concentration. Initially, multilayers of PDADMAC (poly(diallyl dimethyl ammonium chloride)) and PSS (poly(styrene-4-sulfonate), PAA (poly(acrylic acid)) and PDADMAC, PAH (poly(allylamine hydrochloride)) and PAA, and PSS and PAH were prepared under a variety of pH conditions. The physical properties of these films were measured and it was discovered that PAA/PAH multilayers exhibited the largest variations in surface energy (Δ30 mJ/m2) and rigidity (Δ8 GPa). Investigating cell response to different coatings is time consuming, expensive, and prone to error. Therefore, a device was designed that slowly varied the fabrication pH of PAA and PAH orthogonally to each other, providing a technique that enabled the construction of large 2-dimensional films with all possible pH fabrication conditions. Physical property maps were made, and it was discovered that film rigidity was the most crucial determinant for cell survival, and that the neural cells prefer films with a moderate modulus (~500-800 kPa). The ability to reversibly and non-invasively control the physical properties important for bio-activity enables interesting engineering opportunities. By functionalizing PAA with (poly(disperse red 2)) to make pDR2A, and layering it with PDADMAC, the surface energy was reversibly altered by 3 mJ/m2 using linearly polarized light. These changes were stable for days and were attributed to chromophore alignment inside of the film, as measured by birefringence. These results provide some insight on cell-material interactions; however, more importantly, they provide new tools for the investigation of such a complex problem. / La connaissance des interactions entre les cellules et les matériaux synthétiques est cruciale pour la conception de biomatériaux spécialisés. Ces interactions sont principalement basées sur les propriétés physiques des matériaux. Afin d'étudier ces effets, des polyélectrolytes multicouches ont été utilisés. Ces polymères sont capables de couvrir des matériaux en étant soigneusement construit du bas en haut en utilisant une technique couche par couche. Les propriétés physiques d'intérêt biologique de ces revêtements sont possible en modifiant les conditions de leur accumulation, tels que le pH et/ou la concentration de sel. Initialement, des couches de PDADMAC (poly (chlorure de diallyldiméthylammonium)) et PSS (poly (styrène-4-sulfonate), PAA (poly (acide acrylique)) et PDADMAC, PAH (poly (chlorhydrate allyamine)) et AAP, et PSS et les HAP ont été construite sous une variété de conditions de pH. Les propriétés physiques de ces films ont été mesurées et nous avons trouvé que les multicouches HAP/AAP présentaient les plus grandes variations de l'énergie de surface (Δ30 mJ/m2) et la rigidité (Δ8 GPa). Les enquêtes sur les réponses cellulaires aux différents revêtements sont longues et couteuse en plus d'être sujet à l'erreur. Par conséquence, un dispositif a été conçu qui a changé le pH de fabrication de l'AAP et les HAP orthogonalement un à l'autre, cette technique a permis la construction de filmes deux dimensionnelles sur grandes dimensions avec toutes les conditions de fabrication possibles selon la variation du pH. Des cartes des propriétés physiques ont été faites, et il a été découvert que la rigidité des films est le facteur le plus crucial pour la survie des cellules et que les cellules neurales préfère les films avec un module modérée (~ 500-800 kPa). La capacité de contrôler les propriétés physiques importantes de façon réversible et non invasive pour la bio-activité permet des possibilités techniques intéressantes. En fonctionnalisant l'AAP avec du Disperse Red 2 acrylate pour faire pDR2A, des couches construites avec du PDADMAC démontrent une énergie de surface qui peut être modifiée réversiblement de 3 mJ/m2 utilisant de la lumière polarisée linéairement. Ces changements sont stables pendant des jours et sont attribuable à l'alignement intérieur des chromophores du film telle que mesurée par la biréfringence.Ces résultats donnent une de d'information sur les interactions entre les cellules et les matériaux, mais plus important encore, fournissent des nouveaux outils pour l'étude d'un tel problème complexe.

Previous studies reported a unique direction of lamellar twist in banded spherulites of polymers with main-chain chirality, which lead to the suggestion that a correlation exists between the handedness of the helical chain and the twist direction. However, these proposals were presented without identifying underlying reasons for such a correlation. Hence, the goal of this thesis was to identify morphological features that could be ascribed to main-chain chirality, which, in turn, would provide insight concerning the transmission of chirality to asymmetries in various levels of crystalline morphology. / Studies at the molecular level, based on chain-packing simulations showed that main-chain chirality leads to the formation of helices of a given handedness but indicated that the helix handedness does not have the ability to generate asymmetric habits at the next higher dimensional level, which is the chain-folded lamella. This was confirmed by the TEM studies of solution-grown single crystals of the R and S polyenantiomers of poly(epichlorohydrin) (PECH), poly(propylene oxide) (PPrO) and poly(3-hydroxyvalerate) (PHV). / Electron diffraction studies established that chain tilting (considered a root cause of lamellar twisting) is absent in these single crystals. However, this does not eliminate the possibility of an induced chain tilting in stems at growth fronts during fast crystallization from the melt. Indeed, optical microscopy studies of the behavior of spherulites grown from the melt established that the lamellae (fibrils) twist, uniquely in either a right- or left-handed fashion, depending on the chiral identity (R or S) of the polyenantiomer. Although the handedness of the lamellar twist of the R and S polyenantiomers of PECH and PPrO both showed a direct correlation with the handedness of the helical chain, this correlation is not universal. While poly(3-hydroxybutyrate) (PHB) and PHV both form left-handed helices, the directions of lamellar twist are left- and right-handed, respectively. It was also demonstrated that the handedness of spiral patterns developed in banded spherulites of chiral polymers is not rigorously related to the molecular chirality. The overall conclusion is that determination of the ultimate origin(s) of lamellar twisting in banding of polyenantiomers requires further investigations.

Suspensions of rod-like cellulose microcrystallites, 50-250 nm in length and $ sim$7 nm in width, and with negatively charged sulfate groups on the surface have been prepared. When the concentration of cellulose microcrystallites exceeds a critical value, the suspension separates into two phases, forming an upper isotropic phase and a lower chiral nematic anisotropic phase. The critical concentration for phase separation is very sensitive to the ionic strength, particle size, polydispersity of particles, counterion species, and preparation conditions. When the suspension is in pure water and in the biphasic region, the coexisting concentrations in both phases increase with the increase of total cellulose concentration. Suspensions with different counterions have different critical concentrations for phase separation. The critical concentration increases in the order $ rm H sb3{O sp+} < {Na sp+} < {K sp+} < Cs sp+$ for inorganic counterions, and generally increases with increasing counterion size for some organic counterions. The salt-form suspensions demonstrate a good stability with temperature, but the acid-form suspension is unstable at temperatures higher than $50 sp circ$C. The suspensions show induced circular dichroism in the presence of dye, such as Congo red. The anisotropic phase has a very strong negative ICD peak when viewed along the chiral nematic axis, and the peak is much weaker when viewed at right angles to the axis. The isotropic suspension shows a small positive ICD peak. The behavior of the phase separation was compared with the theoretical predictions of Stroobants et al., and a relatively good agreement was obtained between theory and experimental data for suspensions in pure water.

This thesis is made of two parts. In the first part, we study pattern formations and dissipation of energy and matter by using hyperbolic reaction-diffusion equations for reacting systems. Two-dimensional hyperbolic reaction-diffusion equations are numerically solved for the Selkov model and the Brusselator. It is shown that the evolution equations used can give rise to various kinds of patterns such as hexagonal structures, stripes, maze structures, chaotic structures, etc., depending on the values of the reaction-diffusion number and the initial and boundary conditions. The values of the entropy production computed indicate that the system maintains the particular organized local structures at the expense of energy and matter. However, when the system produces a chaotic pattern, the entropy production is lower than the locally organized structures. The phase speed of travelling oscillating chemical waves can be obtained from the linearized hyperbolic reaction-diffusion equations. The Luther-type speed formula is obtained in the lowest order approximation in the case of the Brusselator. The two-dimensional power spectra computed for chaotic patterns still preserve some kind of symmetry. / In the second part of this thesis, the generalized hydrodynamics is applied to calculate the shock profiles, shock widths, and calortropy production for a Maxwell gas. Shock solutions are shown to exist for all Mach numbers. This is in contrast to the Grad moment equation method which does not admit shock solution for $N sb{M} ge 1.65$ and to the method of Anile and Majorana which breaks down for $N sb{M} ge 2.09.$ The energy dissipation in the shock is shown to increase with the Mach number as a power law of the form $(N sb{M} - a) sp{ alpha}$ where a and $ alpha$ are real constants.

<p> Phthalates have attained a great deal of attention recently due to their reported association with endocrine system disturbances. Currently, advanced oxidation processes (AO/RPs) are being considered for use in remediating these chemical contaminants from anthropogenic waste waters; however, there is little known about the kinetics of AO/RP radical reactions with phthalates in water. In this work we investigated the reaction kinetics of the hydroxyl radical, hydrated electron and sulfate radical with a series of phthalates and phthalate monoester metabolites using electron pulse radiolysis. A direct relationship was found between the molecular complexity of the phthalate esters and the natural logarithm of their corresponding hydroxyl radical rate constant. Phthalate monoester metabolites were found to have higher rate constants than the corresponding phthalate diesters of similar molecular complexity. No structural relationship was found between phthalate esters and their corresponding hydrated electron rate constant.</p>