Observation of Photogenerated Polarons in Trans-Polyacetylene

Transient infrared absorption experiments on oriented Durham route polyacetylene have been performed. The alignment of the chains allows one to enhance interchain excitations by pumping with above gap radiation polarized perpendicular to the chain direction. The photoinduced absorption between 0.2 and 0.5 eV is measured with 0.5 ps resolution and we find that it differs from the charged soliton spectrum only for excitation by light polarized perpendicular to the chain direction. We interpret this result in terms of polarons and measure their dynamics and the temperature dependence of their behavior.