THE 1320-NM EXCITED FT-RAMAN SPECTRA OF NA-DOPED TRANSPOLYACETYLENE

The FT-Raman spectra of trans-polyacetylene doped with Na at various c oncentrations were observed with the 1320-nm laser line. Doping-induce d Raman bands for lightly doped trans-polyacetylene were observed for the first time. The observed wavenumbers of the v(1) and v(4) bands (C =C and C-C stretches) of lightly doped trans-polyacetylene are lower t han those of the corresponding bands of pristine trans-polyacetylene, whereas the contrary is the case for heavily doped trans-polyacetylene . The origins of doping-induced Raman bands are discussed in terms of solitons and polarons. (C) 1997 Elsevier Science S.A.