Electron spin resonance studies of magnetic soliton defects in polyacetylene

Abstract

We present electron spin resonance studies of the magnetic defect in undoped polyacetylene. Temperature dependences of the absorption spectra of (CD)x and (CH)x over the range 2–295 K have been obtained. The properties of the magnetic defect in fully isomerized trans samples and in cis-rich samples are compared. The data are consistent with a description in terms of a mobile neutral magnetic defect in the trans polymer and a stationary one in the cis-rich polymer. The spin resonance linewidths are determined by unresolved hyperfine splittings resulting from interaction of the electron spin with many nuclear spins within the envelope of the spatially extended magnetic defect. The results of analyses of the detailed line shapes and linewidths are discussed in terms of the bond alternation domain wall (soliton) model of the magnetic defect.