ESR study of intermediately doped polyacetylene

Motivated by the conjecture of superconductivity by Kivelson and Emery (Synth. Met. 65 (1994) 249), we have carried out the low-field ESR measurements for intermediately either FeCl4− or ClO4− doped polyacetylenes. A trace of superconductivity was absent, and as reasons effects of doping phase separation and of disorder are remarked.