Abstract
We present a complete Raman investigation of segmented trans(CH)
x and trans(CD)
x obtained by introduction of additional atoms (D atoms in (CH)
x and H atoms in (CD)
x) which form sp
3 type defects. Raman spectra are recorded at different excitation wavelengths from the near infrared (
λ
L = 676.4 nm) to the near u.v. (
λ
L = 351.1 nm) and analyzed in the framework of the bimodal distribution model. It is shown in particular that upon introduction of additional atoms, the relative concentration of long conjugated segments is substantially lowered with respect to that of short ones. On the other hand, it is observed that even for a high concentration of sp
3 defects (y = 0.27), long conjugated segments are still present in the polymeric chains. This result suggests that a clustering of defects occurs in agreement with the optical band gap values measured in these materials. This hypothesis is corroborated by results obtained from energy calculations performed on similar compounds.