Dynamics of vibronically excited fluorene–Arn (n=4, 5) clusters

The fluorene–Ar4 cluster has been shown to exhibit two distinct isomers when formed in a molecular beam. Resonance enhanced multiphoton ionization and mass analyzed threshold ionization experiments have been performed to investigate the structural properties, energetics and dynamics of these clusters when excited to vibronic bands in the S1 electronic state, with a specific interest in measuring isomer interconversion. At 208 cm−1 excess energy in the S1 isomer interconversion is not observed in the Ar4 cluster. Dissociation of the Ar5 cluster from the 722 cm−1 band is shown to produce both Ar4 isomers.