Soliton band formation

Using this model, the doping of polyacetylene proceeds by the interaction of dopants with solitons initially present in the polymer, then by polaron formation and at even higher doping levels by soliton formation. The soliton states then broaden into a soliton band that eventually fills the gap, giving a continuum of energy levels and a metallic state. 

SoKtons produced in polyacetylene are delocalized over approximately 12 CH units, with the maximum charge density to the dopant counterion. Soliton formation results in the creation of a new localized electronic state which is in the middle of the energy gap. At a high level of doping the charged sohtons produce soliton bands that can merge to behave hke a metalhc conductor. 

Optical Signatures of Solitons, Polarons, and Bipolarons The formation of these excitations generates energy levels corresponding to optical transitions below the fundamental absorption that between the valence and the conduction band in one-electron models (but see Section... 

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