PICOSECOND PHOTOINDUCED TRANSIENT RESONANT RAMAN-SCATTERING IN CIS-RICH POLYACETYLENE

We have measured the picosecond transient dynamics of photoexcitations in cis- and trans-(CH)x segments in a cis-rich (CH)x sample using the technique of transient photoinduced resonant Raman scattering (TPRRS). In this technique the transient response of individual resonantly enhanced phonons in the system can be selectively monitored. This allowed us, for the first time, to study the time evolution of photoexcitations in cis-(CH)x segments. The photoexcitation dynamics between zero and 1000 ps can be described in both isomers by a power-law decay. We found, however, a faster photoexcitation decay in cis segments, in agreement with the current theoretical model for one-dimensional semiconductors.