Estupiñán Edgar G, Klippenstein Stephen J, Taatjes Craig A
Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, USA.
J Phys Chem B. 2005 May 5;109(17):8374-87. doi: 10.1021/jp046514s.
The formation of HO(2) in the reactions of C(2)H(5), n-C(3)H(7), and i-C(3)H(7) radicals with O(2) is investigated using the technique of laser photolysis/long-path frequency-modulation spectroscopy. The alkyl radicals are formed by 266 nm photolysis of alkyl iodides. The formation of HO(2) from the subsequent reaction of the alkyl radicals with O(2) is followed by infrared frequency-modulation spectroscopy. The concentration of I atoms is simultaneously monitored by direct absorption of a second laser probe on the spin-orbit transition. The measured profiles are compared to a kinetic model taken from time-resolved master-equation results based on previously published ab initio characterizations of the relevant stationary points on the potential-energy surface. The ab initio energies are adjusted to produce agreement with the present experimental data and with available literature studies. The isomer specificity of the present results enables refinement of the model for i-C(3)H(7) + O(2) and improved agreement with experimental measurements of HO(2) production in propane oxidation.
采用激光光解/长程频率调制光谱技术，研究了C₂H₅、正丙基和异丙基自由基与O₂反应中HO₂的形成。烷基自由基通过烷基碘的266nm光解形成。烷基自由基与O₂后续反应生成HO₂的过程通过红外频率调制光谱进行跟踪。通过第二个激光探针直接吸收自旋轨道跃迁上的光，同时监测I原子的浓度。将测量的曲线与基于先前发表的势能面上相关驻点的从头算表征的时间分辨主方程结果得到的动力学模型进行比较。调整从头算能量以使其与当前实验数据和现有文献研究结果一致。本研究结果的异构体特异性使得异丙基 + O₂反应模型得以完善，并与丙烷氧化中HO₂生成的实验测量结果取得了更好的一致性。
