Photoexcitation dynamics in polyacetylene probed by transient photoinduced resonant Raman scattering

We have measured photoexcitation dynamics in the picosecond time domain in fully trans and partially isomerized (CH)X and (CD)X films with different cis/trans content ratios, using the technique of transient photoinduced resonant Raman scattering. Following the distinctively different decay kinetics of cis and trans resonantly enhanced vibrations, we observed an intersystem crossing of photoexcitations from cis to trans segments which is dominated by a diffusion process in the cis segments, with a time constant between 24 and 215 ps depending on the cis/trans ratio.