Square wave frequency modulation in pure nuclear quadrupole resonance spectroscopy

The effect of square wave modulation frequency on the signal intensities obtained with a super-regenerative spectrometer is investigated. The dependence of the nuclear quadrupole resonance signal intensity obtained with a number of compounds is found to be related to the apparent spin-spin relaxation time of the resonant nuclei. An analysis indicates that the signal response of the resonant nuclei is the same regardless of modulation frequency. However, the fundamental Fourier component is directly related to the apparent spin-spin relaxation time.

Quench frequency effects on the nuclear quadrupole resonance of orthoiodophenol

When the quench frequency of a self-quenched spectrometer is varied, the plot of the 127I nuclear quadrupole resonance signal against quench frequency in o-iodophenol, at room temperature, exhibits a number of maxima. Hitherto, analogous plots with chlorine compounds, using self-quenched spectrometers, gave only a maximum; this is briefly discussed.