Liquid crystals spin averaging techniques

Rusling and his collaborators have obtained reversible voltammetric responses of cyt. P-450cam. hemoglobin, Mb, cyt. c, and chlorella ferredoxin cast in bquid crystal films or composites of liquid crystal and Nafion [79-81] on gold electrodes. The structure of the cast films was characterized by low angle x-ray diffraction. The structures of Mb and cyt. P-450cam hi the cast film were characterized by UV-vis. Electron Spin Resonance (ESR), and reflectance Fourier Transform Infrared (FT-IR) spectroscopic techniques, and are shown to be similar to the native conformations. Visible linear dichroism and ESR anisotropy showed that Mb is specifically oriented in the static films. The orientation of the heme plane of Mb averaged 60° with respect to the normal to the film plane, and distributions are rather broad. 

Often, in liquid-phase as well as in single-crystal NMR work, the samples are deliberately spun, often at special orientations (magic angle) relative to B. This will average out dipolar interactions, often narrowing the observed lines by substantial amounts. For example, see Ref. 3, Section 7.10 and Ref. 4, Chapter 8. Under some circumstances, additional lines (spinning sidebands) are generated by the MAS technique.32-34... 

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