We use a configurational-coordinate method to treat anharmonic quantum lattice fluctuations in nondegenerate conducting polymers. The direct-subgap optical-absorption and luminescence spectra are calculated for polythiophene and poly(3-hexylthienylene). Comparison with experiment is made.

• Received 7 July 1988

DOI:https://doi.org/10.1103/PhysRevB.39.5152