We present a theoretical study of soliton formation in long-chain polyenes, including the energy of formation, length, mass, and activation energy for motion. The results provide an explanation of the mobile neutral defect observed in undoped ${\left(\mathrm{CH}\right)}_x$. Since the soliton formation energy is less than that needed to create band excitation, solitons play a fundamental role in the charge-transfer doping mechanism.

• Received 15 March 1979

DOI:https://doi.org/10.1103/PhysRevLett.42.1698