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 $$\text{D(⊥ab)=3\hspace{0.17em}}\exp \text{\hspace{0.17em}(−22\hspace{0.17em}}\mathrm{kcal}\mathrm{/RT)}$$ and $$\text{D(⊥ac)=16\hspace{0.17em}}\exp \text{\hspace{0.17em}(−24\hspace{0.17em}}\mathrm{kcal}\mathrm{/RT).}$$ The possible mechanism, the anisotropic nature of the diffusion process, and the results as compared with a previous investigation are discussed in detail.