Diffusion IQENS

Figure 11. Translational diffusion coefficients of EABAC measured using NMR (circles) and IQENS (squares). The open points are for Q perpendicular to the director and the filled points are for Q parallel to it (from [56], with permission SA=smetic A, SmA).

Incoherent quasi-elastic neutron scattering (IQENS) has been used to investigate the dynamics of nematic phases. When a monochromatic beam of neutrons is scattered from a nematic liquid crystal the shape of the elastic line in the energy-transfer spectra gives information on the molecular dynamics. A quasi-elastic neutron scattering measurement may be used to investigate the diffusive motions of the molecules in the nematic phase. The translational diffusion coefficients may be determined and localised motions such as molecular rotation and internal rotations may also be characterised. 

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