Theses and Dissertations from UMD

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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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    ISOTOPE EFFECTS IN THE STATE-RESOLVED COLLISION DYNAMICS OF HIGHLY EXCITED MOLECULES
    (2014) Echebiri, Geraldine Onyinyechi; Mullin, Amy S; Chemistry; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The importance of highly excited molecules in the fields of combustion and atmospheric chemistry makes it essential to study pathways by which energy is lost from the excited molecule. One such pathway is by inelastic collisions with a bath molecule. In this dissertation, the collisional relaxation of highly excited pyrazine-h4 (Evib = 37900 cm-1) and pyrazine-d4 (Evib = 37900 cm-1) with HCl (300 K) is studied. The outcomes of the inelastic collision studies reveal quantum state-energy gaps of molecules and their intermolecular interactions affect the mechanism and dynamics of collisional energy transfer. The results from collisional relaxation of pyrazine-h4 (Evib = 37900 cm-1) with HCl were compared to those from collisional relaxation of pyrazine-h4 (Evib) with DCl in order to deduce the effects of quantum state-energy gaps on the dynamics of collisional energy transfer. The comparison shows the dynamics for collisional deactivation of pyrazine-h4 (Evib) with HCl and DCl are different, and are possibly due to their intermolecular interactions with pyrazine-h4 (Evib. The data for collisional relaxation of pyrazine-d4 (Evib = 37900 cm-1) with HCl were compared to those for pyrazine-h4 (Evib) + HCl collisions in order to determine the contributions of near-resonant vibrational energies of the collision partners on the collision dynamics. The comparison shows the energy transfer dynamics for collisional quenching of pyrazine-h4 (Evib) and pyrazine-d4 (Evib) with HCl are similar. The similarity in their energy transfer dynamics suggests near-resonance effects are not contributing significantly to the collision dynamics.