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In this thesis, we develop analytical models for quantum systems and perform theoretical investigations on several dynamical processes in condensed phases. First, we study charge-carrier mobilities in organic molecular crystals, and develop a microscopic theory that describes both the coherent band-like and incoherent hopping transport observed in organic crystals. We investigate the structures of polaron states using a variational scheme, and calculate both band-like and hopping mobilities at a broad range of parameters. Our mobility calculations in 1-D nearest-neighbor systems predict universal band-like to hopping transitions, in agreement with experiments. Second, motivated by recent developments in quantum computing with solid-state systems, we propose an effective Hamiltonian approach to describe quantum dissipation and decoheren...
Includes bibliographical references (p. 281-311).
Includes bibliographical references (leaves 46-48).
The biosynthesis of asparagine-linked glycoproteins, highly conserved throughout all eukaryotes, requires a dolichylpyrophosphate-linked tetradecasaccharide precursor (Dol-PP-GlcNAc2Man9Glc3), from which the tetradecasaccharide is transferred co-translationally to nascent polypeptides in the lumen of the ER by the multimeric membrane-bound enzyme, oligosaccharyl transferase (OT). The saccharide donor is assembled by a series of membrane-bound enzymes, which together comprise the dolichol pathway. Despite over two decades of genetic and bioinformatics approaches that have identified the vast majority of dolichol pathway genes in yeast, the roles of two mannosyltransferases in the pathway, Alg2 and Algl 1, remained ambiguous. This thesis describes the biochemical studies that were carried out to clarify these roles. The substrate specifi...
The dinitrogen reduction capability of a series of new triamidoamine based molybdenum compounds has been studied. The synthesis of a number of different triamidoamine ligands, and their resulting molybdenum compounds, is described. While symmetric variants containing electron-withdrawing hexaisopropyl terphenyl substituents can successfully catalyze dinitrogen reduction to ammonia, only the most bulky unsymmetric "hybrid" compounds can facilitate this reaction. Further study of these systems reveals a different pathway for catalyst failure than had previously been observed. It was discovered that, at least for the smaller ligands, a base-catalyzed hydrogenase reaction occurs at a rate much faster than that of ammonia formation. The Mo(IV) diazenido (LMoN2H) compound undergoes net H. loss, forming the Mo(III) dinitrogen (LMoN2) species ...
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