Comparative study of shirakawa and naarmann-theophilou type polyacetylenes by ESR

Summary form only given. Spin dynamics study of the neutral soliton was reported at 300 K, to compare the Shirakawa (SPA) and the Naarmann and Theophilou (NT-PA) type polyacetylenes in the view point of the neutral soliton dynamics. ESR line width was measured as a function of frequency which was scanned from 10 to 2,000 MHz. With a least square fitting of the Lorentzian line shape to the ESR spectrum, resolution of the line width was enhanced down to mG. As the S-PA several samples prepared with different way were used for comparison. The frequency dependence of the line width is well consistent with quasi-one-dimensional diffusion of the neutral soliton. The analyzed diffusion rates along (D/sub /) and across (D/sub /spl perp/) the chain will be comparatively discussed. Characteristic features are as follows; (i) the diffusion rate along the chain D/sub /, shows a weak correlation with the width by trapping /spl Delta/H/sub trap/ and NT-PA has the smallest D/sbu /, and the largest /spl DeltaH/sub trap/ in spite of its highest electrical conductivity, (ii) the diffusion rate across the chain D/spl perp/ showed no meaningful change for the studied samples. As a conclusion we can not find any meaningful correlation between the neutral soliton dynamics and the electrical conductivity, as suggested by Wang et al.*