Dynamics of solitons in polyacetylene with interchain coupling

The interchain charge transfer and interactions of two chains are studied numerically through the dynamics of charged and neutral solitons in the presence of an electric field by using the Su-Schrieffer-Heeger model. The electric field is introduced in terms of a time-dependent vector potential which is included in the Hamiltonian through a Peierls substitution of the phase factor to the transfer integral. The effects of confinement on the soliton motion are determined. In particular, the viability of a single moving soliton to cross an interacting region between two parallel chains is analyzed, and its relationship to soliton velocity and interaction region extent is determined. The interchain charge-transfer probability is considered. The charge-transfer probability in a collision between a charged and a neutral soliton belonging to neighboring chains is determined. It is shown that a pair of solitons, one on each chain, can move freely together in an oscillatory way, without any confinement. The oscillation frequency is estimated and its relationship to experimental data is clarified.