Subgap absorption and quantum lattice fluctuation in degenerate and nondegenerate polymers

By using a simple model of soliton-antisoliton pairs to simulate the quantu m lattice fluctuations in one-dimensional organic polymers, in which the su bgap absorption results from the transitions between the lowest unoccupied and the highest occupied levels off the conduction and valence bands, respe ctively, in the soliton-antisoliton excitations. There is no gap in the abs orption. Our result indicates clearly that the nondegeneracy of ground - st ates suppresses the quantum fluctuations, so that the subgap absorption is reduced and there is a related clear onset in the absorption spectrum of no ndegenerate polymers, which is in agreement with experiments.