Electronic spectroscopy of a cyclopentafused PAH cation, the fluorene+: comparison between gas phase and matrix spectra

The D3←D0 electronic transition of the cold fluorene+ cation, C13H10 +, has been measured in the gas phase and in a neon matrix. The gas phase spectrum exhibits broad vibronic bands of Lorentzian lineshape (full width at half maximum (FWHM)=140 cm−1) revealing a very short lifetime for the D3 state. The comparison between the spectra taken in these two media, which are extremely similar, brings new information on the perturbation by the neon matrix. An upper limit of the relaxation rate due to intermolecular dynamics in the matrix has been derived and no effect due to solvation on the non-adiabatic coupling is observed.