Laser excited infrared fluorescence in COF2: Equilibration and relaxation of the C=O and C–F stretching modes

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Abstract
Over 30 different CO2 laser lines have been found to produce strong laser induced fluorescence at λ=5 μ from the ν1 (C=O stretch) and 2ν2 (C–F stretch) states in COF2. The observed fluorescence is of two distinct types consistent with two different primary pumping mechanisms: (1) laser pumping 0→ν2 followed by collisional filling of 2ν2 via excited state–excited state collisions, and (2) direct laser pumping of ambient molecules in ν2 via the ν2→2ν2 transition. The ν1 and ν2 manifolds reach vibrational steady state within 30 gas kinetic collisions, while approximately 500 collisions are required to relax this localized energy to the remaining vibrational modes.