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Abstract:
The static director distribution in thin nematic liquid crystal cells, subject to both electric and magnetic
fields, has been investigated using a combination of deuterium nuclear magnetic resonance (NMR) spectroscopy
and continuum theory in terms of the director distribution function, which gives the probability density for
finding the director at a given orientation. A series of deuterium NMR spectra for the nematic liquid crystal,
4−pentyl−d2−4−cyanobiphenyl deuteriated in the α position of the pentyl chain were acquired as a function of
the applied electric field. This powerful experimental technique allowed us to observe uniform and nonuniform
director alignment depending on the angle between the two fields and their relative strength. On the basis of the
detailed experimental results, we have explored the factors that influence the nature of both the uniform and the
nonuniform director distributions. We have discussed the questions that are raised by our attempt to understand
the static director distribution as a function of the angle between the two fields. We have discovered that the
alignment of the director at the surface of the Teflon spacers is essential in addition to the random variation in
the cell thickness in order to account for the static director distribution determined from the NMR spectra
