Femtosecond optical dynamics of alpha-conjugated hexamethylsexithiophene in solution

摘要

The photoexcited state dynamics of methyl-substituted sexithiophene in solution is investigated by using the femotosecond pump and probe technique. Intraband thermalization of S_1 could be monitored following thespectral relaxation of the stimulated emission. Electron-ring torsion coupling is proposed to play a fundamental role in this process leading to a more planar geometry of the exicted state. The population dynamics is understood taking into account intersystem crossing to the triplet manifold as the main non-radiative decay channel.