Probing excited state dynamics of cis,cis-1,3-cyclooctadiene with time-resolved photoelectron spectroscopy

Photoinduced isomerization dynamics play an important role in conjugated molecular systems with double bonds. We extend previous studies from small rigid systems, such as trans-1,3-butadiene ( C₄H₆ ) and 1,3-cyclohexidiene ( C₆H₈ ), to a larger and more flexible molecule, cis,cis-1,3-cyclooctadine ( C₈H₁₂). We perform time-resolved photoelectron spectroscopy ( TRPES ) measurements on cis,cis-1,3-cyclooctadiene, and we interpret the measurement with trajectory surface hopping calculations. The measurements indicate that the molecule undergoes rapid internal conversion to the ground state, and the features in the measured photoelectron spectra are interpreted in terms of ionization to several states of the molecular cation.