Molecular geometry of cis- and trans-polyacetylene by nutation NMR spectroscopy

The carbon-carbon bond lengths in polyacetylene have been directly measured with use of nutation NMR spectroscopy. 1.36 and 1.44 were found for the double and single bonds, respectively, in trans-(CH)x, and 1.37 was found for the double bond in the cis isomer. Over the temperature range 4.2-300 K, the dynamical single-double bond interchange predicted for chains in trans-(CH)x containing a mobile soliton defect was not observed. © 1983 The American Physical Society.