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 ⩽ 15, Ka = 0), with other parameters held fixed, left the rate unaffected. Implications are discussed within the framework of statistical rate theories.