The gas-phase kinetics of reactions of alkali metal atoms with nitric oxide

Time-resolved atomic resonance absorption spectroscopy was employed, with flash-photolysis generation of atomic potassium and sodium at 734 K, to investigate the kinetics of K + NO + Ar and Na + NO + Ar. The low-pressure limit recombination rate constants are (1.0 +/- 0.2) x 10(-31) and (1.9 +/- 0.5) x 10(-32) cm(6) molecule(-2) s(-1), respectively. Mainly ionic, tripler state adducts are predicted, RRKM modeling yielded K-NO and Nas NO bond dissociation enthalpies of 104 and 66 kJ mol(-1), which compare well with UQCISD(T)/6-311 + G(2d) ab initio values of 81 and 68 kJ mol(-1), respectively. For Li + NO + Ar, the predicted binding energy is 134 kJ mol(-1), which yields a predicted rate constant of 1.4 x 10(-31) cm(6) molecule-2 s(-1).