Call number: LD2668 .T4 1986 M35 / Master of Science / Physics

Chan Wang-Ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 87-94). / Abstracts in English and Chinese. / TITLE PAGE --- p.i / THESIS COMMITTEE --- p.ii / ABSTRACT (ENGLISH) --- p.iii / ABSTRACT (CHINESE) --- p.v / ACKNOWLEDGEMENTS --- p.vi / TABLES OF CONTENTS --- p.vii / LIST OF FIGURES --- p.ix / LIST OF TABLES --- p.xii / Chapters / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Laser absorption spectroscopy of C2 Phillips System --- p.4 / Chapter A. --- Introduction --- p.4 / Chapter B. --- Quantum mechanics of C2 --- p.13 / Chapter C. --- Experimental details --- p.18 / Chapter D. --- Observation --- p.24 / Chapter E. --- Spectroscopic analysis --- p.30 / Chapter F. --- Discussion --- p.43 / Chapter G. --- Conclusion --- p.48 / Chapter 3 --- Computational study of O2-(rare gas) van der Waals complexes --- p.49 / Chapter A. --- Background --- p.49 / Chapter B. --- Van der Waals complexes: an overview --- p.60 / Chapter C. --- Methodology --- p.62 / Chapter D. --- Results --- p.65 / Chapter E. --- Discussion and Conclusion --- p.81 / Chapter 4 --- Concluding Remarks --- p.85 / REFERENCES --- p.87

Ten gaseous transient metal-containing molecules have been synthesized and studied by high resolution spectroscopy. Transient molecules are molecules with a short lifetime, and they play an important role in chemistry because they are reaction intermediates. One of the difficulties faced in studying transient molecules is their typically low concentrations under laboratory conditions. Three types of sources were used to generate these molecules: 1) an emission source that combines a high temperature furnace with an electrical discharge was used to generate SbH, SbD, TeH, TeD, CdH2, CdD2, HZnCl and BeF2; 2) a King furnace (carbon tube furnace) was used to synthesize CoS; 3) a Broida-type oven (metal flow reactor) was used to generate SrOD. Two spectroscopic techniques were employed to study these molecules: 1) Fourier transform infrared emission spectroscopy was used to study SbH, SbD, TeH, TeD, CdH2, CdD2, HZnCl, BeF2, and CoS. 2) Laser-induced fluorescence spectroscopy was employed to study SrOD. One or two lasers were used to excite the SrOD molecules from the ground state to excited electronic states and then these SrOD molecules relaxed back to the ground state by emitting fluorescence, which was detected by a photomultiplier tube. Significantly-improved spectroscopic constants have been obtained for SbH, SbD, TeH and TeD. For SbH and SbD, the infrared X 3– vibration-rotation bands and the near infrared b 1+ – X 3– transition were observed and rotationally analyzed, and a Hund’s case (a) fit was performed for each of the four observed SbH isotopologues. For TeH and TeD, the X 23/2 vibration-rotation bands and the near infrared X 21/2– X 23/2 transition have been observed and rotationally analyzed, and Hund’s case (a) and case (c) fits were performed for each of the ten observed TeH isotopologues. New spectroscopic constants were obtained for HZnCl, CdH2 and CdD2. These three molecules have been successfully generated in the gas phase for the first time. The fundamental band and one hot band were obtained for the H–Zn stretching mode (1) and for the antisymmetric stretching mode (3) of CdH2 and CdD2. A least-squares fit was performed for each of the four observed HZnCl isotopologues and the twelve observed CdH2 isotopologues For the first time, a complete set of molecular constants for all three vibrational frequencies was experimentally determined for BeF2. Thirteen new hot bands were rotationally analyzed and the 1, 2, and3 vibrational frequencies were directly determined by fitting nineteen bands together. The traditional equilibrium vibrational and rotational constants were obtained for BeF2 by simultaneously fitting the observed vibrational term values and B rotational constants. New spectroscopic constants were obtained for two electronic states of CoS and SrOD, respectively. The A 4i – X 4i and B 4i – X 4i transitions of CoS and the and transitions of SrOD were observed for the first time. Hund’s case (c) fits were performed for the CoS transitions and Hund’s case (a) fits were performed for the SrOD transitions.

Ten gaseous transient metal-containing molecules have been synthesized and studied by high resolution spectroscopy. Transient molecules are molecules with a short lifetime, and they play an important role in chemistry because they are reaction intermediates. One of the difficulties faced in studying transient molecules is their typically low concentrations under laboratory conditions. Three types of sources were used to generate these molecules: 1) an emission source that combines a high temperature furnace with an electrical discharge was used to generate SbH, SbD, TeH, TeD, CdH2, CdD2, HZnCl and BeF2; 2) a King furnace (carbon tube furnace) was used to synthesize CoS; 3) a Broida-type oven (metal flow reactor) was used to generate SrOD. Two spectroscopic techniques were employed to study these molecules: 1) Fourier transform infrared emission spectroscopy was used to study SbH, SbD, TeH, TeD, CdH2, CdD2, HZnCl, BeF2, and CoS. 2) Laser-induced fluorescence spectroscopy was employed to study SrOD. One or two lasers were used to excite the SrOD molecules from the ground state to excited electronic states and then these SrOD molecules relaxed back to the ground state by emitting fluorescence, which was detected by a photomultiplier tube. Significantly-improved spectroscopic constants have been obtained for SbH, SbD, TeH and TeD. For SbH and SbD, the infrared X 3– vibration-rotation bands and the near infrared b 1+ – X 3– transition were observed and rotationally analyzed, and a Hund’s case (a) fit was performed for each of the four observed SbH isotopologues. For TeH and TeD, the X 23/2 vibration-rotation bands and the near infrared X 21/2– X 23/2 transition have been observed and rotationally analyzed, and Hund’s case (a) and case (c) fits were performed for each of the ten observed TeH isotopologues. New spectroscopic constants were obtained for HZnCl, CdH2 and CdD2. These three molecules have been successfully generated in the gas phase for the first time. The fundamental band and one hot band were obtained for the H–Zn stretching mode (1) and for the antisymmetric stretching mode (3) of CdH2 and CdD2. A least-squares fit was performed for each of the four observed HZnCl isotopologues and the twelve observed CdH2 isotopologues For the first time, a complete set of molecular constants for all three vibrational frequencies was experimentally determined for BeF2. Thirteen new hot bands were rotationally analyzed and the 1, 2, and3 vibrational frequencies were directly determined by fitting nineteen bands together. The traditional equilibrium vibrational and rotational constants were obtained for BeF2 by simultaneously fitting the observed vibrational term values and B rotational constants. New spectroscopic constants were obtained for two electronic states of CoS and SrOD, respectively. The A 4i – X 4i and B 4i – X 4i transitions of CoS and the and transitions of SrOD were observed for the first time. Hund’s case (c) fits were performed for the CoS transitions and Hund’s case (a) fits were performed for the SrOD transitions.

Reverse transcription of HIV-1 genome involves multiple nucleic acids structural rearrangements chaperoned by nucleocapsid protein (NC). One such critical step is that the DNA transactivation response element (TAR) anneals to it complementary RNA region on the genome. It has been challenging to investigate mechanistic details on the annealing process because of the involvement of heterogeneous sets of protein/nucleic acid complexes. Here, we use single-molecule spectroscopy to study the NC induced melting of nucleic acid structure and the annealing activity of different regions along TAR structure. We find that NC induced secondary fluctuations are limited to the terminal stems, and the mechanism for the fluctuations is complex. By employing complementary targeted oligomers, we kinetically trap and investigate stable states of the putative nucleation complexes for the annealing process. This single molecule spectroscopy method directly probes kinetic reversibility and the chaperone role of NC at various stages along the reaction sequence. The new results lead to detailed understanding of NC chaperoned reverse-annealing and the partially annealed conformational sub-states. Argininamide, because of its specific binding to the loop regions of TAR, was studied on its specific inhibition to strand transfer. The loopmediated annealing is found to be more potentially inhibited than stem-mediated one.

No description available.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (PhD) - Swinburne University of Technology, Centre for Atom Optics and Ultrafast Spectroscopy, 2009. Thesis (PhD) - Australian Research Council, Centre of Excellence for Quantum-Atom Optics, 2009. / Thesis submitted for the degree of Doctor of Philosophy, Centre for Atom Optics and Ultrafast Spectroscopy, and, ARC Centre for Quantum-Atom Optics, Swinburne University of Technology, 2009. Typescript. Bibliography: p. 131-149.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Krzysztof Szalewicz, Dept. of Physics and Astronomy. Includes bibliographical references.

Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 103-108). Also available for download via the World Wide Web; free to University of Oregon users.