UBC Theses and Dissertations
Photoelectron spectroscopy of some polyatomic molecules Chau, Foo-Tim
The photoelectron spectrum of a molecule displays the kinetic energy distribution of the ejected photoelectron by monochromatic radiation. From the fine structure on a photoelectron band, valuable information about the bonding properties of both the molecule and its cation, and the ionic geometry can be obtained. The work described in this thesis falls into two main parts. The first is concerned with the quantitative application of the Franck-Condon principle to group VI hydrides, nitrous oxide and dihaloethylenes, by which the geometries of their molecular ions were obtained. An iterative method was devised to facilitate the computational procedure. The second part of this thesis contains the results of photoelectron spectroscopic studies on several halogenated molecules, viz. fluorotribromo-methane, fluorotrichloromethane, 1,2-dichloro-, 1,2 dibromo-, and 1,2 diiodo-ethanes and their perfluoro derivatives, 1,2 bromochloroethane, 1,2-dibromo-1,1-difluoroethane, cis and trans 1,2 difluoroethylenes, and 1,2 dibromo-cyclohexane. One electron models including spin orbital coupling, and through bond and through space interactions, are applied to most of these molecules as well as the dichloro-, dibromo-, and diiodoethylenes. The NMR chemical shifts, nuclear quadrupole coupling constants, electronegativity of the halogen atom and the force constants of the molecules studied are discussed in the light of the calculated molecular orbital parameters.
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