An experimental investigation of the effect of rotation on the rate of unimolecular decomposition of NO2

The effect of rotational excitation on the rate of unimolecular decomposition has been examined for a benchmark system. NO2 molecules having specific excitations were selected by pumping rotational components of the (1,0,1)<--(0,0,0) combination band with the output from a 0.02 cm(-1) resolution parametric oscillator, and reaction rates were obtained by applying the picosecond-resolution pump-probe technique to these tagged species. The addition of up to 100 cm(-1) of rotational energy (N less than or equal to 15, K-a = 0), with other parameters held fixed, left the rate unaffected. Implications are discussed within the framework of statistical rate theories. (C) 1997 Elsevier Science B.V.