Dynamic effects of the impurity potential and electron interactions on a soliton intrans-polyacetylene

Abstract
We calculate the potential energy of a charged soliton on a chain of polyacetylene in the presence of an (interstitial) impurity atom and Hubbard on-site interactions. Using this potential, we find the lowest two bound states of the soliton which determine the ‘‘Goldstone-mode’’ contribution to infrared absorption. The wave functions are then used to incorporate soliton dynamics into the calculation of optical absorption by the chain. Also included is a study of interaction effects on neutral solitons in pure polyacetylene.