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In polycrystalline samples, NMR "powder spectra" are broad and much structural informa ion is ost as a result of the orientational disorder In th' Lett F n zs er Fourier-transform R m zero magnetic field is described. With no f d d no pre erre irection in space, all direct in ter crystallites contribute equivalently and resolved d 1 1'tt' ve zpo ar sp ettings can be interpreted irect y in terms of internuclear distances. This open th 'bl'-f s e posse ray-o molecular strucure etermination without the need for single crystals or oriented samples

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Articles you may be interested inInvestigation of molecular structure in solids by twodimensional NMR exchange spectroscopy with magic angle spinning A field theory of random heteropolymers near solid surfaces: Analysis of interfacial organization and adsorption-desorption phase diagram Determination of hyperfine interactions from the magnetic field dependence of nuclear modulation frequencies: An electron spin echo envelope modulation study of protons in γirrradiated potassium dihydrogen arsenate Methods are described and demonstrated for detecting the coherent evolution of nuclear spin observables in zero magnetic field with the full sensitivity of high field NMR. The principle motivation is to provide a means of obtaining solid state spectra of the magnetic dipole and electric quadrupole interactions of disordered systems without the line broadening associated with random orientation with respect to the applied magnetic field. Comparison is made to previous frequency domain and high field methods. A general density operator formalism is given for the experiments where the evolution period is initiated by a sudden switching to zero field and is terminated by a sudden restoration of the field. Analytical expressions for the signals are given for a variety of simple dipolar and quadrupolar systems and numerical simulations are reported for up to six coupled spin-l/2 nuclei. Experimental results are reported or reviewed for 1H, 20, 7Li, i3C, and 27 AI nuclei in a variety of polycrystalline materials. The effects of molecular motion and bodily sample rotation are described. Various extensions of the method are discussed, including demagnetized initial conditions and correlation by two-dimensional Fourier transformation of zero field spectra with themselves or with high field spectra.