Femtosecond studies of electronic relaxation. Vibrational relaxation, and rotational diffusion in all-trans-1,8-diphenyl-1,3,5,7-octatetraene

A study was conducted to analyze electronic relaxation, rotational diffusion and vibrational relaxation in all-trans-1,8-diphenyl-1,3,5,7-octatetraene (DPO). DPO was prepared by recrystallization from ethanol. A pump-probe apparatus was utilized for the transient absorption measurements, and was based on a Ti:sapphire laser system. Results indicated fast photophysical processes and a solvent dependence that does not correlate to an energy gap law.