Kinetics of the F+NO₂+M->FNO₂+M reaction studied by pulse radiolysis combined with time-resolved IR and UV spectroscopy

The title reaction was initiated by the pulse radiolysis of SF6/NO2 gas mixtures, and the formation of FNO2 was studied by time-resolved infrared spectroscopy employing strong rotational transitions within the nu(1) and nu(4) bands of FNO2. The pressure dependence of the formation kinetics was studied with SF6 pressures of 5-1000 mbar at 298 K. Comparative studies were carried out by monitoring the decay kinetics of NO2 at 445 nm using pressures of 100-1000 mbar at 295 and 341 K. The observed pressure dependence is represented in terms of a fall-off curve with the following values of the limiting high- and low-pressure rate coefficients, k(rec,proportional to) = (2.1 +/- 1.0)x 10(10) (T/300)(0.5) M(-1) s(-1) and K-rec,K-0/[SF6] = (3.8 +/- 1.8) x 10(12) (T/300)(-24) M(-2) S-1 in the temperature rang 200-400 K, and with a broadening factor, F-cent = 0.587X (T/300>(-0.32).