Absolute Rate Constants for the Reactions of O(3P) with Several Molecules

Abstract

Abstract Absolute rate constants were measured for several reactions of ground-state oxygen atoms at 296±2 K. The pulse-radiolysis of O2, CO, or CO2 in the He diluent was used to produce oxygen atoms, and the atomic concentration was monitored by the resonance absorption. The measurements were made in the pressure range from 50 to 950 Torr (1 Torr \simeq133.3 Pa). The rate constants thus obtained were (2.5±0.3)×10−34 for O+O2+He and (1.0±0.2)×10−35 for O+CO+He in units of cm6 molecule−2 s−1 (1 cm6 molecule−2 s−1\simeq3.626×1035 m6 mol−2 s−1). For simple olefins, the following bimolecular rate constants (k⁄10−12 cm3 molecule−1 s−1) were obtained: Ethylene (1.0±0.2), propene (4.7±0.3), 1-butene (4.7±0.5), trans-2-butene (23±3), cis-2-butene (20±3), 2-methylpropene (17±2), 2-methyl-2-butene (55±5), 1,3-butadiene (20±2), (1 cm3 molecule−1 s−1\simeq6.022×1017 m3 mol−1 s−1). These rate constants were in fair agreement with the literature values.