Dielectric tensor and the local electric field in naphthalene

Abstract

The complete dielectric tensor of naphthalene single crystals has been measured by a low‐frequency capacitative technique at 295 °K. The principal components are 2.25 ± 0.07, 2.87 ± 0.05, and 3.43 ± 0.08, with the 1 axis making an angle of 28 ± 2.5° with the + a axis. These results are consistent with previous results for anthracene, though different from an earlier set of results used in analysing Hall measurements. The effect of this difference on the results of this Hall analysis is probably small. The measured dielectric tensor has been used to calculate the average local electric field, which resembles that in anthracene but is more anisotropic. The local field has in turn been used to calculate the off‐diagonal drift mobility component for electrons and holes from the various experimental diagonal components. An expression has also been derived for the local‐field correction required in comparing theoretical hopping Hall mobilities with experiment.