Influence of the rf Field Inhomogeneity on Nutation NQR Spectra of Spin 3/2 Nuclei in Powders

Abstract

This paper treats the stability of two superposed gravitating streams rotating about the axis transverse to the horizontal magnetic field. The critical wave number for instability is found to be affected by rotation for propagation perpendicular to the axis about which the system rotates. The critical wave number for instability is not affected by rotation when waves propagate along the axis of rotation. The critical wave number is affected by both the magnetic field and the streaming velocity in both cases. Both the magnetic field and the rotation are stabilizing, while the streaming velocity is destabilizing.

Lineshape Analysis of 2D NMR and NQR Nutation Spectra of Integer and Half-Integer Quadrupolar Nuclei

“…However, due to the very broad nutation spectrum involved, this method leads to a large error and cannot be recommended. An important cause for nutation spectrum broadening is the inhomogeneity of the rf field [7]. The effect of rf inhomogeneity cannot simply be described with a Lorentzian broadening because a spread in u> { will also cause a spread in the r parameter, and will thus change the whole nutation spectrum.…”

“…As shown in [5], the 2D-nutation NQR lineshape and frequency are considerably modified by the offset of the spectrometer frequency from resonance. The influence of relaxation processes [6] and the rf field inhomogeneity [7] on the form of nutation line and on location of characteristic singularities in the powder pattern have also been considered. The analytical formulas for the lineshape of the powder nutation spectrum are given in [8].…”