Measurements of Soliton Trapping and Motion in Trans-Polyacetylene Using Dynamic Nuclear Polarization

The motion of solitons in undoped trans-(CH)x is studied over the temperature range 1.5–300 K using dynamic nuclear polarization. The results of a theoretical model for the combined solid state and Overhauser effects in terms of the time dependence of the electron nuclear interaction due to motion of electrons is presented. Its application to the experiment shows that most of the solitons are trapped below 30 K and that the mobile solitons above 30 K have a diffusion coefficient that is approximately proportional to the square root of the temperature. At 300 K the time for a soliton to diffuse its length is greater than or equal to 1.7 × 10−11 seconds.