Temperature dependence of the limiting low- and high-pressure rate constants for the CH3O+NO2+He reaction over the 250–390 K temperature range

The laser photolysis laser-induced fluorescence technique was used to measure the pressure (pT=50–600 Torr) and temperature (T=250–390 K) dependence of the rate constant for the CH3O+NO2 reaction in He. CH3ONO/NO2/He mixtures were photolysed at 248 nm and the CH3O radical generated was monitored by LIF emission. Combined with previously reported rate coefficients at low pressures and after subtracting the disproportionation contribution to this reaction, our corrected kinetic experimental data, k1a(T), were fitted to the Troe expression, yielding the limiting low- (k1a0) and high-pressure (k1a∞) rate constants. The temperature dependence found was (k1a0±2σ)=(3.93±0.05)×10−29(T/300)−(1.74±0.40) cm6 molecule−2 s−1 and (k1a∞±2σ)=(2.40±0.02)×10−11(T/300)−(0.88±0.32) cm3 molecule−1 s−1. These results are compared with those previously reported at room temperature.