UBC Theses and Dissertations
Studies in nuclear magnetic and nuclear quadrupole resonance spectra Cranna, Norman Greig
Standard techniques of radio-frequency nuclear resonance spectroscopy have been applied to further studies of the interaction between atomic nuclei in crystals and the crystalline electric' field gradients at the nuclear sites. Observations have been made on the nuclear magnetic resonance spectra of Al²⁷, Li⁶, Li⁷ and Si²⁹ in single crystals of LiAl(Si0₃)₂ (spodumene) in strong magnetic fields. Results from the Al²⁷ spectrum provided improved values of the field gradient constants of spodumene and a check on the adequacy of second and third order perturbation theory in describing the electrostatic perturbation of the magnetic energy levels; these results also provided an experimental check on a proposed new method of nuclear spin determination. The Li⁶ and Li⁷ measurements provided a more accurate value of the quadrupole moment ratio for this pair of isotopes. Observations on the Si²⁹ spectrum support; existing evidence that the spin of Si²⁹ is 1/2. A super-regenerative spectrometer has been built for the detection of nuclear magnetic resonances and nuclear electric quadrupole resonances. Preliminary tests indicate that it will detect resonances in solids at low frequencies which could not be detected with the continuous-wave type of spectrometer. A pure quadrupole resonance in Na₂B₄O₇.4H₂O (kernite) has been detected at 1.27 Mc./sec. using this super-regenerative spectrometer. This represents a pure quadrupole resonance of the lowest frequency reported to date.
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