The thermal conductivity and the thermal diffusivity of aligned $n\mathrm{CB}$ samples $(n=5,\dots ,9)$ has been measured with a photopyroelectric technique. An odd-even effect has been found in the values of these two quantities for homeotropic samples with increasing $n.\mathrm{}$ The results can be interpreted in terms of a model proposed by Urbach, Hervet, and Rondelez. This model, which takes into account not only the geometrical dimensions of the liquid crystal molecules but also their average mutual distances, has been also used to account for the observed anisotropy in the thermal diffusivity.

• Received 24 March 1998

DOI:https://doi.org/10.1103/PhysRevE.58.5860