DYNAMICS OF SOLITON PAIRS IN POLYACETYLENE

The dynamics of soliton pairs and polaron pairs is numerically studied using the Su-Schrieffer-Heeger model extended to include the short-ranged Coulomb interactions. The unrestricted time-dependent Hartree-Fock approximation is used. As a trigger to put the solitons and polarons in motion, spatially uniform external electronic fields are introduced to the system through time-dependent vector potentials, which are included into the model as a phase factor of the transfer integral. It is found that the pair of charged solitons with opposite charges, that of neutral solitons with parallel spins and that of polarons with opposite charges and antiparallel spins are highly stable against collisions, while the pair of neutral solitons with antiparallel spins is unstable. The charge and/or spin transfer during the collisions is also discussed.