Abstract: The proton spin-lattice relaxation time T₁ in undoped cis-polyacetylene, trans-polyacetylene and partially deuterated trans-polyacetylene, and the proton spin-lattice relaxation time in rotating frame T_1ρ in undoped trans polyacetylene were measured.
The results indicate that trans-polyacetylene does contain a lot of spin centers called solitons, which dominate the proton relaxation in it.Solitons are mobile,but localized. Not only the multiexponential decay in T_1ρ -process,but also the independence of its decay rate from the temperature and the magnitude of the spin-locking magnetic field are interpreted by using the model of localized solitons.