Vibrationally unrelaxed fluorescence in matrix isolated CF2

The CF₂ emission spectrum in rare gas solids involves both the symmetric vibrations, ν₂ (668 cm^?1) and ν₁ (1120 cm^?1). A vibrationally unrelaxed emission is observed following selective excitation of the higher vibrational levels in the ν₂ manifold, and we measure vibrational relaxation rates of 2 × 10⁸/sec and 1.1 × 10⁸/sec, respectively, for the 2-1 and 1-0 relaxation in argon. All the vibrational bands show a strong coupling to the lattice modes, with a weak ZPL and strong phonon wing. This results from the change in geometry between the ground and excited electronic states.