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    • Thesis


    • Authors: McNally, Ann Maurine (2006)

    • The first part of this thesis focuses on the photosensitized degradation of lignin model compounds. The kinetics and mechanism of the photodegradation of monomeric and dimeric models of lignin that vary in their number of methoxy substituents is described. Specifically, the kinetics of the reaction of lignin models with singlet oxygen and excited sensitizer (both are reactive species present in sunlit natural waters) is reported and used to elucidate the mechanism of these reactions. The second part of this thesis focuses on the quantification of the generation of singlet oxygen by natural organic matter in Lake Superior and its Western tributaries. Furfuryl alcohol, whose primary pho...

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    • Thesis


    • Authors: Liu, Yonglin (2006)

    • Although carbonylnitrenes have been well studied by product analysis, very few direct spectroscopic observations of these reactive intermediates have been made. This thesis focuses on the direct observation and photochemical reactivity of carbonylnitrenes. Aroyl azides are studied as photochemical precursors to aroylnitrenes. Due to instability and low UV-Vis absorption of alkylcarbonyl azides, alternative photochemical precursors to alkylcarbonylnitrenes have been developed. The chemistry of carbonylnitrenes has been studied both by product analysis performed with and without trapping reagents (alkene, oxygen, and H-atom donors) and by nanosecond time-resolved infrared spectroscopy. ...

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    • Thesis


    • Authors: Nangia, Shikha (2006)

    • This thesis presents progress in six areas of quantum photochemistry: (i) a new algorithm for carrying out efficient semiclassical dynamical calculations using a trajectory surface hopping method for systems with weakly coupled electronic states, (ii) an improved treatment of electronic coherence and decoherence in electronically nonadiabatic molecular collisions, (iii) calculations of coupled diabatic potential energy surfaces by a multi-reference electronic structure method, (iv) comparison of adiabatic ground-state and excited-state adiabatic surfaces calculated by multi-reference electronic structure methods to those calculated by a single-reference method-of-moments and coupled c...

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    • Thesis


    • Authors: Gadde, Suresh (2006)

    • The research reported in this thesis details the synthesis, characterization, electrochemical and photochemical studies of noncovalently linked porphyrin-fullerene based donor-acceptor systems. The first chapter gives an introduction that briefly summarizes the significant events that occur in natural photosynthetic systems, the importance of artificial photosynthetic models and finally, lists new developments in model biomimetic systems of this type. The second chapter discusses synthesis of control compounds and physical methods used in later chapters. The third chapter focuses on the investigation of covalently linked porphyrin-fullerene dyads. A discussion of the role of axially l...

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    • Thesis


    • Authors: Werner, Jeffrey Jason (2006)

    • There is growing concern over the introduction of pharmaceutical pollutants to the environment. Loss processes such as photolysis are expected to be important in predicting the environmental fate of a given pharmaceutical. Environmental photochemical kinetics were investigated for several pharmaceutical compounds. Direct photolysis quantum yield values were determined for mefenamic acid, tylosin, tetracycline, and chlortetracycline. The photolysis of mefenamic acid was sensitized by a reaction with excited triplet-state natural organic matter. Tylosin photolysis occurred in two steps: a reversible, efficient photoisomerization equilibrium via rotation about a carbon-carbon double bond...