Diffusion in Organic Crystals. I. Self-Diffusion in Anthracene

Self-diffusion in high-purity anthracene single crystals has been measured by means of a microtome sectioning technique with anthracene-9-14C as a tracer, in the temperature range from 140° to 196°. For diffusion perpendicular to the ab and ac planes, the data were respectively fitted as D(⊥ab)=3 exp (−22 kcal/RT)and D(⊥ac)=16 exp (−24 kcal/RT).The possible mechanism, the anisotropic nature of the diffusion process, and the results as compared with a previous investigation are discussed in detail.