Y. Furukawa et al., RAMAN-SPECTRA OF HEAVILY SODIUM-DOPED TRANSPOLYACETYLENE AND THE RADICAL-ANIONS OF DIPHENYLPOLYENES AND DITHIENYLPOLYENES, Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals, 256, 1994, pp. 721-726
The Raman spectra of trans-polyacetylene doped with sodium (Na) at the
maximal level have been measured with excitation laser lines between
488.0 and 1064 nm. These spectra have been compared with those of mode
l compounds, i.e., the radical anions of alpha, omega-diphenylpolyenes
(Ph-(CH=CH)(n)-Ph, n = 3, 4) and alpha, omega-di-2-thienylpolyenes (T
h-(CH=CH)(n)-Th, n = 3 and 4). The similarity between the Raman spectr
a of Na-doped polyacetylene and those of the radical anions indicates
that the observed bands of Na-doped polyacetylene arise from charged d
omains generated by Na-doping. The observed large wavenumber dispersio
n of the C=C stretching vibration of the charged domains suggests a br
oad distribution of localization lengths in the charged domains.