Observation of a defect dependent ‘pinning mode’ in Durham-Polyacetylene

We present photoinduced IR-spectra of Durham-Polyacetylene, where we observed for the first time a new clearly resolvable structure in the ‘pinning mode’ (PM). We study the influence of air on the PM and discuss a derivativelike feature around the C-H-out-of-plane-deformation mode, which may help to clarify the nature of the ‘shape modes’. From our experimental results, we conclude that solitons move to chains with higher lc,eff after photoexcitation.