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|Title:||Microwave-Frequency Conductivity of Alpha Silver-Iodide, Microwave Spectroscopy of Hydrogen-Bonded Species, and Design of a High-Temperature Nozzle Source|
|Author(s):||Soper, Paul Donald|
|Department / Program:||Chemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Chapter I reports the measurement of silver ion conductivities in the alpha phase of silver iodide over the frequency range 4 to 40 GHz. The conductivity is independent of frequency over this range and has a value of 1.2 (ohm-cm)('-1) at 429 K. These results are combined with other recent measurements to interpret the ionic transport in terms of motion between the tetrahedral sites of the AgI lattice.
The remainder of the thesis reports based on the use of a microwave-frequency spectrometer incorporating a Fabry-Perot cavity, a pulsed supersonic nozzle beam, and Fourier transform techniques. Chapter II reports the microwave rotational spectra, molecular geometries, and intermolecular interaction potentials for dimers of carbon monoxide with hydrogen chloride and hydogen fluoride (OC-HCl and OC-HF). Nuclear quadrupole coupling constants are reported for ('35)Cl and ('37)Cl in OC-HCl and for deuterium in OC-DF. Values of the H, ('19)F and D, ('19)F nuclear spin - nuclear spin coupling constants are reported for OC-HF and OC-DF. Both the OC-HCl and OC-HF dimers are linear at equilibrium with binding occurring through a hydrogen bond to carbon atom of carbon monoxide. This is the first observation of a hydrogen bond to a carbon atom in the gas phase.
Chapter III reports the microwave rotational spectra, ('14)N nuclear quadrupole coupling constants and H, ('19)F nuclear spin - nuclear spin coupling constants of the dimers formed by hydrogen fluoride with cyanogen and nitrogen (NCCN-HF and N(,2)-HF). These dimers are both linear at equilibrium. The differences in the two ('14)N nuclear quadrupole coupling constants within each dimer have been interpreted in terms of the Townes-Dailey theory. It is found that polarization occurs within the cyanogen and nitrogen components of the dimers. This polarization corresponds to a negative charge of ca 0.02e on N(2) in N(1)CCN(2)-HF and also of ca 0.02 e on N(2) in N(1)N(2)-HF. Separation of vibrational and electrical effects on the magnitudes of the ('14)N nuclear quadrupole coupling constants was made possible by the symmetry of the NCCN and N(,2) components of the two dimers. This represents the first separation of these effects, without which estimation of polarization is impossible.
Chapter IV reports the ('14)N nuclear quadrupole coupling and H, ('19)F nuclear spin - nuclear spin coupling constants of the dimer between acetonitrile and hydrogen fluoride (CH(,3)CN-HF). A vibrational normal mode analysis using force constants from earlier infrared and relatively high-temperature microwave measurements allowed separation of vibrational and electrical effects in the magnitude of the ('14)N nuclear quadrupole coupling constant and led to an estimation of the excess charge on the nitrogen in the dimer. It is ca 0.03e more negative in the dimer than it is in free acetonitrile. This represents the first separation of these effects by the use of results from spectroscopy at temperatures high relative to those resulting from a supersonic expansion (10 K or lower).
The final chapter describes additions made to the spectrometer in order to extend the range of possible components of dimers to solids and liquids of low vapor pressure at room temperature. No rotational transitions from dimers involving such components have yet been observed. Specific modifications of the oven design are suggested and future experiments are proposed.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981.
|Date Available in IDEALS:||2014-12-15|