QUANTITATIVE LASER-INDUCED FLUORESCENCE SPECTROSCOPY OF THE CF A(2)SIGMA(-X(2)PI TRANSITION - ELECTRONIC-TRANSITION DIPOLE-MOMENT FUNCTION AND PREDISSOCIATION())

Several previously unmeasured aspects of the quantitative spectroscopy of the CF A(2) Sigma(+)-X(2) Pi transition have been investigated exp erimentally. Ground state CF radicals were prepared in an rf discharge chamber and laser-induced fluorescence (LIF) was excited on the A-X t ransition. Relative vibrational transition probabilities were deduced from dispersed fluorescence spectra emitted by CF A(2) Sigma(+) (upsil on' = 0 and 1), from which the form of the electronic transition dipol e moment function, R(e)(r), could be assessed. Reasonable agreement wa s found with a previous ab initio prediction of a moderate decline in R(e)(r) over the relevant, fairly limited range of internuclear distan ces sampled by the experiment. Weak fluorescence has also been detecte d for the first time from the heavily predissociated upsilon' = 2 leve l. A rotationally-resolved LIF excitation spectrum was obtained. Lower and upper limits on the upsilon' = 2 fluorescence lifetime were estim ated to be 0.4 and 2 ns, respectively. There is a weak, if any, declin e in the upsilon' = 2 fluorescence quantum yield with rotational quant um number up to ca. 20.5. These observations are shown to be consisten t with a predissociation mechanism involving tunneling through the pre dicted barrier to dissociation which results from an avoided crossing at longer internuclear distances.