Polarons, bipolarons, and their interactions in cis -polyacetylene

Explicit solutions for the Brazovskii-Kirova continuum model of cis-polyacetylene are presented for the following three configurations: two polarons, two bipolarons, and a polaron and a bipolaron coexisting on a single chain. The results show that two polarons attract each other with a long-range potential reflecting large spatial extension of the polarons and that the attracted polarons form a bipolaron; two bipolarons repel each other; and polarons and bipolarons can freely pass through each other without attractive or repulsive interactions.