Optical Absorption by Phonons around a Soliton in a Model oftrans-Polyacetylene (CH)x

The dynamical conductivity due to linear modes (phonons) around a soliton is calculated in a continuum model of trans -(CH) x using numerical data for the linear modes obtained in the previous paper. In the case of the neutral soliton, there is no contribution from the linear modes to the conductivity, while the positively and negatively charged solitons have the same phonon assisted conductivity. Linear modes with odd parity are shown not to contribute to the conductivity. Two of the three localized modes are found to be infra-red active. The results are compared with experiments on the infra-red absorption in lightly doped trans -(CH) x and on the photo-induced absorption in undoped samples.