Conversion ofcis-polyacetylene totrans-polyacetylene during doping

An experimental study of the infrared properties of iodine-doped and ammonia-compensated polyacetylene has been carried out. Doping of trans-polyacetylene leads to strong absorption lines at 870 and 1390 ${\mathrm{cm}}^{\ensuremath{-}1}$ along with a broad "midgap" absorption at higher frequences. Compensation reduces all of these features in equal proportion. The doping-related absorption in cis-polyacetylene as well as the effects of compensation are essentially identical to that in the trans form. This result shows that the doping in cis samples occurs in trans regions present in the sample or created in it by the doping process.