Kinetic study in a microwave-induced plasma afterglow of the Fe (a 5D4) reaction with NO2 from 303 to 814 K

Abstract

A kinetic study of the reaction of ground state Fe atoms (a 5D4) with NO2 has been performed in a fast-flow reactor. A microwave-induced plasma afterglow system with H atoms reacting with the gaseous FexCl3x(g) oligomers was used as Fe atom source. The Fe atoms were monitored by atomic absorption spectroscopy (AAS) at 248.3 nm. The rate constant k1 of the reaction Fe + NO2 → products has been determined at temperatures between 303 and 814 K and was found to be equal to k1 = (4.8+0.7−0.6) × 10−10exp(−(4.5 ± 0.4)/RT kJ mol−1) cm3 molecule−1 s−1. The mechanistic implications in terms of the “electron-jump” mechanism are also discussed and it was concluded that the concept of “harpooning” is not applicable to reaction (1). Instead, the value of k1 can remarkably well be simulated in terms of the simple gas kinetic collision model.