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The quadrupolar echo Fourier transform technique effectively eliminates spectral distortion in deuterium nuclear magnetic resonance (2H nmr) spectroscopy due to the finite time required for recovery of the rf receiver following the application of an rf pulse. For broad 2H nmr spectra, the influence of the quadrupolar interactions during the rf pulses leads to another important distortion effect. An exact correction for this effect is calculated using the formalism of Vega and Pines. A comparison of the theoretical distortion correction factor with experiment is made and found to be satisfactory.

Proton magnetic resonance (1H NMR) has been used to compare the local orientational order of acyl chains in phospholipid bilayers of multilamellar and small sonicated vesicular membranes of dipalmitoyllecithin (DPL) at 50 degrees C and egg yolk lecithin (EYL) at 31 degrees C. The orientational order of the multilamellar systems was characterized using deuterium magnetic resonance order parameters and 1H NMR second moments. 1H NMR line shapes in the vesicle samples were calculated using vesicle size distributions, determined directly using electron microscopy, and a theory of motional narrowing, which takes into account the symmetry properties of the bilayer systems. The predicted non-Lorentzian line shapes and widths were found to be in good agreement with experimental results, indicating that the local orientational order (called "packing" by many workers) in the bilayers of small vesicles and in multilamellar membranes is substantially the same. This results was found to be true not only for the largest 1H NMR line associated with the nonterminal methylene protons but also for the resolved 1H NMR lines due to the alpha-CH2 and the terminal CH3 positions on the acyl chain. Analysis of the vesicle 1H NMR spectra of EYL taken with different medium viscosities yielded a value of approximately 4 X 10(-8) cm2 s-1 for the lateral diffusion constant of the phospholipid molecules at 31 degrees C.

Nuclear spin relaxation in a hexagonal lyotropic liquid crystal J. Chem. Phys. 95, 6945 (1991); 10.1063/1.461506Nuclear magnetic resonance determination of the CF2 order parameter tensor in a lyotropic liquid crystal

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