14N nuclear quadrupole resonance investigations

The interaction between non-spherical nuclear charge distribution and the electric field gradient is described. Expressions for the energy levels (I = 1), the nuclear quadrupolar resonance, NQR, transition frequencies and line shape are derived. The general equations to obtain the inverse line width parameter, T$ sb2 sp star,$ from the self-quenched super-regenerative oscillator, SRO, NQR spectra are derived and tested.The construction and operation of the $ sp{14}$N Sullivan and Dean SRO spectrometers are described. Limits in the sensitivity of the SRO to yield T$ sb2 sp star$ data are discussed. The operation and the constraints in obtaining line width data from a pulsed-FT spectrometer are given. The temperature dependence of $ sp{14}$N NQR frequencies, T$ sb2 sp star$ and line widths of series of anilines and hexamethylenetetramine are reported.The NQR frequency and the contribution of static and dynamic effects to the line width are discussed as a function of temperature. The observed phase transitions are discussed