Nuclear magnetic resonance spectroscopy line shape

Cotton, F. A., Chemical Applications of Group Theory, 2nd ed., Wiley-Interscience, 1971. Cotton, F. A., Quart. Rev., 1966, 20, 389 (reviews polyhedra of transition metal atoms). Emsley, J. W., J. Feeney and L. H. Sutcliffe, High Resolution Nuclear Magnetic Resonance Spectroscopy, Vol. 1, Pergamon Press, 1965 (Chapter 9 covers basic theory of the effect of site exchange on nmr line shapes). 

The potential of nuclear magnetic resonance spectroscopy for studying liquid crystalline systems is discussed. Typical spectra of nematic, smectic, and cholesteric mesophases were obtained under high resolution conditions. The observed line shape in the cholesteric phase agrees with that proposed on the basis of the preferred orientation of this phase in the magnetic field. The line shapes observed in lyotropic smectic phases appear to be the result of a distribution of correlation times in the hydrocarbon portions of the surfactant molecules. Thermotropic and lyotropic phase transitions are easily detected by NMR and agree well with those reported by other methods. The NMR parameters of the neat and middle lyotropic phases allow these phases to be distinguished and are consistent ivith their proposed structures. 

For the investigation of the molecular dynamics in polymers, deuteron solid-state nuclear magnetic resonance (2D-NMR) spectroscopy has been shown to be a powerful method [1]. In the field of viscoelastic polymers, segmental dynamics of poly(urethanes) has been studied intensively by 2D-NMR [78, 79]. In addition to ID NMR spectroscopy, 2D NMR exchange spectroscopy was used to extend the time scale of molecular dynamics up to the order of milliseconds or even seconds. In combination with line-shape simulation, this technique allows one to obtain correlation times and correlation-time distributions of the molecular mobility as well as detailed information about the geometry of the motional process [1]. 

From its very beginning nuclear magnetic resonance (NMR) was used to unravel dynamic processes in amorphous matter, where the high selectivity of this technique was exploited. Recent progress has largely benefited from the development of multidimensional NMR spectroscopy, significantly extending the traditional techniques such as spin-lattice relaxation and line-shape analyses. Modern NMR techniques helped a lot to understand the molecular dynamics in disordered systems such as the a-process. 

In Chap. 1 is written by Saburo Nasu, the reader will find a general introduction to Mossbauer Spectroscopy. What is the Mossbauer effect and What is the characteristic feature of Mossbauer spectroscopy These questions are answered briefly in this chapter. Mossbauer spectroscopy is based on recoilless emission and resonant absorption of gamma radiation by atomic nuclei. Since the electric and magnetic hyperfine interactions of Mossbauer probe atom in solids can be described from the Mossbauer spectra, the essence of experiments, the hyperfine interactions and the spectral line shape are discussed. A few typical examples are also given for laboratory experiments and new nuclear resonance techniques with synchrotron radiation. 

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