Comparative study on shirakawa polyacetylene and naarmann-theophilou-type polyacetylene: neutral soliton dynamics

A spin dynamics study of the neutral soliton is reported at room temperature to compare Shirakawa (S-PA) and Naarmann-Theophilou (NT-PA) type polyacetylenes. Intrachain (D⊥) and interchain (D⊥) diffusion rates, and a residual ESR width are discussed. A qualitative difference in dimensionality of spin dynamics, as reported by Wang et al. (Phys. Rev. B, 44 (1991) 12 070), was not observed at all. On the other hand, a weak correlation was found between D⊥ and the residual ESR linewidth that is caused by trapping of the neutral soliton. It is concluded that the difference of conductivity in both polyacetylenes is dominated by the higher density and the higher degree of orientation in the NT-PA film than the S-PA film.