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 decomp osition has been examined for a benchmark system. NO2 molecules having specific excitations were selected by pumping rotational components o f the (1,0,1)<--(0,0,0) combination band with the output from a 0.02 c m(-1) resolution parametric oscillator, and reaction rates were obtain ed 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 fix ed, left the rate unaffected. Implications are discussed within the fr amework of statistical rate theories. (C) 1997 Elsevier Science B.V.