Ultrafast Photoisomerization Studies of 1,4-Distyrylbenzene

In this thesis, we report the ultrafast spectroscopic studies of cis/trans photo- isomerization for three 1,4-distyrylbenzene (DSB) isomers: trans,trans-DSB, cis,trans-DSB, and cis,cis-DSB. A two-color pump-probe transient absorption setup was built to investigate their isotropic and anisotropic transient behaviors simultaneously, as well as the temporal evolution of their excited-state spectra. The population relaxation dynamics and cis/trans photoisomerization process were carefully examined by the isotropic transient study. The transient anisotropy study provided evidences of molecular structures during the photoisomerization process. Finally, a comprehensive model was proposed to elucidate the main characteristics and essential time constants of the cis/trans photoisomerization processes among the three 1,4-distyrylbenzene isomers.