Studies of polaron and or bipolaron formation in short segments of polymers

We study the problem of two polyene segments of variable lengths to which w e have added two electrons. Given that the first electron is localized on o ne chain, where will the second electron go? Will it go to chain 1 and form a bipolaron (soliton-antisoliton) of charge -2e or will it go to chain 2 a nd the two chain segments will each contain a polaron? The energy differenc e as a function of chain lengths for the two cases is calculated and a cros s-over from polarons to intra chain soliton -antisolitons is found.