Gas-phase kinetics of the N + C2N reaction at low temperature

The rate of the gas-phase N(4S) + C2N(2?i) reaction has been measured in a continuous supersonic flow reactor down to 54 K through the relative-rate method using the N(4S) + OH(X2?) ? H(2S) + NO(X2?) reaction as a reference. The microwave discharge technique was employed to produce high concentrations of atomic nitrogen. Pulsed laser photolysis of precursor molecules Cl3C2N and H2O2 at 212 nm in situ led to C2N and OH radical formation, respectively. The rate constant is shown to be approximately independent of temperature, in contrast to previous studies of atom-radical reactions involving atomic nitrogen. While the reaction rate is faster than previously estimated, astrochemical simulations indicate that this reaction is probably only a minor source of CN radicals in dense interstellar clouds.