Xiang Tiancheng, Liu Kunhui, Zhao Shaolei, Su Hongmei, Kong Fanao, Wang Baoshan
State Key Laboratory of Molecular Reaction Dynamics and Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
J Phys Chem A. 2007 Sep 27;111(38):9606-12. doi: 10.1021/jp074058c. Epub 2007 Aug 17.
The multichannel reaction of the C(2)Cl(3) radical with O(2) has been studied thoroughly by step-scan time-resolved Fourier transform infrared emission spectroscopy. Vibrationally excited products of Cl(2)CO, CO, and CO(2) are observed and three major reaction channels forming respectively ClCO + Cl(2)CO, CO + CCl(3)O, and CO(2) + CCl(3) are identified. The vibrational state distribution of the product CO is derived from the spectral fitting, and the nascent average vibrational energy of CO is determined to be 59.9 kJ/mol. A surprisal analysis is applied to evaluate the vibrational energy disposal, which reveals that the experimentally measured CO vibrational energy is much more than that predicted by statistical model. Combining previous ab initio calculation results, the nonstatistical dynamics and mechanism are characterized to be barrierless addition-elimination via short-lived reaction intermediates including the peroxy intermediate C(2)Cl(3)OO* and a crucial three-member-ring COO intermediate.
通过步进扫描时间分辨傅里叶变换红外发射光谱对C(2)Cl(3)自由基与O(2)的多通道反应进行了深入研究。观测到了Cl(2)CO、CO和CO(2)的振动激发产物，并确定了分别形成ClCO + Cl(2)CO、CO + CCl(3)O和CO(2) + CCl(3)的三个主要反应通道。通过光谱拟合得出产物CO的振动态分布，确定CO的初始平均振动能量为59.9 kJ/mol。应用意外分析来评估振动能量分布，结果表明实验测得的CO振动能量远高于统计模型预测值。结合先前的从头算计算结果，非统计动力学和机理的特征是通过包括过氧中间体C(2)Cl(3)OO*和关键的三元环COO中间体在内的短寿命反应中间体进行无势垒加成-消除反应。
