This thesis discusses two ensembles, the study of which was dependent upon the controllable production of cold gas-phase samples using supersonic beams. The experiments on DNA bases and base clusters were carried out in Germany at the Max Born Institute. The experiments anticipating the construction of a molecular beam slower were carried out in the United States at the University of Texas at Austin. Femtosecond pump-probe techniques were employed to study the dynamics and electronic character of DNA bases, pairs and clusters in the gas phase. Experiments on DNA base monomers confirmed the dominance of a particular relaxation pathway, the nπ* state. Competition between this state and another proposed relaxation pathway was demonstrated through observations of the DNA base pairs and base-water clusters, settling a recent controversy. Further, it was determined that the excited state dynamics in base pairs is due to intramolecular processes rather than intermolecular processes. Finally, results from base-water clusters confirm that microsolvation permits comparison with biologically relevant liquid phase experiments and with ab initio calculations, bridging a long-standing gap. A purely mechanical technique that does not rely upon quantum or electronic properties to produce very cold, very slow atoms and molecules would be more generally applicable than current approaches. The approach described here uses supersonic beam methods to produce a very cold beam of particles and a rotating paddle-wheel, or rotor, to slow the cold beam. Initial experiments testing the possibility of elastic scattering from a single crystal surface were conducted and the implications of these experiments are discussed. / text
| Identifer | oai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/29674 |
| Date | 04 May 2015 |
| Creators | Smith, Valoris Reid |
| Source Sets | University of Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | electronic |
| Rights | Copyright is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works. |
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