PUMP PROBE FLUORESCENCE STUDIES OF EXCIMER FORMATION AND DISSOCIATION FOR THE VANDERWAALS DIMER OF FLUORENE

Pump-probe experiments have been performed on the excited-state dynamics of the fluorene van der Waals dimer isolated in a supersonic expansion. When the pump laser excites the dimer into its S1 state, a spectral hole is observed in the dimer transitions due to the excited-state dimer undergoing an efficient excimer formation. This hole-burning technique has been used to demonstrate that the spectral congestion of the S1 spectra of the dimer originates from homogeneous sources. The dissociation of the excimer in its ground electronic state has also been probed directly by observing monomer fragments of fluorene produced by the dissociation process. The results suggest the formation of vibrationally highly excited monomer fragments following the electronic relaxation of the excimer.