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|Title:||The Study of Various Hydrogen-Bonded Complexes Using Pulsed, Fourier-Transform Fabry-Perot Microwave Techniques|
|Author(s):||Aldrich, Peter Douglas|
|Department / Program:||Chemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||A series of studies is presented in which microwave spectra are obtained for various hydrogen-bonded, gas phase complexes between small hydrocarbons and hydrogen halides or HCN. The pulsed Fourier-transform, Fabry-Perot technique is used allowing nuclear quadrupole coupling and other various hyperfine interactions to be observed in addition to the normal rotational spectra. Details of structure and binding are elucidated for the complexes from zero-field spectroscopic constants. Observation of the rotational Zeeman effect for complexes involving cyclopropane gives additional electronic distribution information for the complexes and is shown to indirectly give magnetic properties for cyclopropane. The complexes discussed include complexes between cyclopropane and HCl, HF, and HCN and complexes between ethylene or acetylene and HCl or HCN. Also, the extension of the pulsed Fourier-transform, Fabry-Perot microwave technique to study electronically excited triplet states is discussed.
The first two chapters deal with complexes involving cyclopropane and discuss the zero-field and Zeeman microwave spectroscopic constants. In addition, the magnetic properties of cyclopropane are obtained from those of the complexes by subtracting out the vibrationally averaged effects of the binding partners.
The following four chapters deal with the acetylene-HCN, acetylene-HCl, and ethylene-HCl complexes mostly in terms of their zero-field, ground vibrational state rotational spectra. Strength of binding, vibrational motions in the complex, nuclear spin statistics, charge rearrangement in the subunits, along with structural details are discussed for the three complexes. Electric field gradients at quadrupolar nuclei are examined in terms of perturbations introduced upon complexation in order to explain experimental anisotropies and inadequacies in projection models.
The final chapter discusses the combination of the pulsed Fourier-transform, Fabry-Perot microwave technique with electronic excitation through flashlamps to achieve microwave spectra for electronically excited triplet species. The feasibility of having sufficient signal-to-noise is discussed in detail for small carbonyls where the n (--->) (pi)* transition is excited prior to microwave excitation.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
|Date Available in IDEALS:||2014-12-15|