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Rydberg Time-Of-Flight And Imaging Probes Of The Velocity-Dependent Hydrogen Atom Spin Polarization, Bernadette Michlewicz Broderick
Rydberg Time-Of-Flight And Imaging Probes Of The Velocity-Dependent Hydrogen Atom Spin Polarization, Bernadette Michlewicz Broderick
Wayne State University Dissertations
Insights into electron spin and nuclei are central to the field of chemical reaction dynamics. Of particular note is the study of spin-polarized hydrogen (SPH) atoms, which result from photodissociation of molecules. Examination of the detailed H-atom spin polarization is achieved by determining the projection of the electron spin onto the probe laser direction. In doing so, its angular distribution, complex dissociation pathways, and coherent excitation mechanisms may be revealed. Approaches to detect SPH atoms are experimentally challenging due to the difficulty associated with probing ground-state H atoms through isolated fine structure levels, which is the only direct way to …
Astrochemical Dynamics: Fundamental Studies Relevant To Titan's Atmosphere, Wilson Kamundia Gichuhi
Astrochemical Dynamics: Fundamental Studies Relevant To Titan's Atmosphere, Wilson Kamundia Gichuhi
Wayne State University Dissertations
This work presents results of primary fundamental photodissociation and state-specific ion-molecule dynamical studies that are relevant to understanding the formation and growth mechanisms of unsaturated hydrocarbon molecules, haze layers and aerosols in Titan's upper atmosphere. In the diacetylene dimer, it is shown, via laboratory studies combined with electronic structure calculations that the photodissociation of the dimer readily initiates atomic hydrogen (H) loss and atomic H transfer reactions forming two prototypes of resonantly stabilized free radicals, C8H3 and C4H3, respectively. In ethylamine cation, high-level ab initio calculations identify the complex dissociation pathways for the ground state CH3CH2NH2+ radical cation at 233.3 …
Photodissociation Dynamics In Titan's Atmosphere, Welvidanalage Ruchira Silva
Photodissociation Dynamics In Titan's Atmosphere, Welvidanalage Ruchira Silva
Wayne State University Dissertations
Photodissociation dynamics of molecules relevant to understanding Titan's atmosphere (diacetylene, cyanoacetylene and heptane isomers) are carried out under collisionless condition using the DC slice imaging technique. In diacetylene photodissociation, two-photon processes dominate at 243 nm and 212 nm whereas at 121.6 nm, a one-photon dissociation process dominates. Direct measurement of the lifetime of metastable triplet diacetylene confirms sub-microsecond lifetimes. Photodissociation of cyanoacetylene at 193.3 nm proceeds on the S1 potential energy surface with an exit barrier. In heptane photodissociation, the dissociation occurs on the ground state or low-lying triplet states with nonradiative electronic relaxation. Time-of-flight mass spectroscopy studies in this …