Yu Hua-Gen, Muckerman James T, Francisco Joseph S
Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
J Chem Phys. 2007 Sep 7;127(9):094302. doi: 10.1063/1.2770463.
The reaction of HOCO with O atoms has been studied using a direct ab initio dynamics approach based on the scaling all correlation UCCD/D95(d,p) method. Ab initio calculations point to two possible reaction mechanisms for the O+HOCO-->OH+CO2 reaction. They are a direct hydrogen abstraction and an oxygen addition reaction through a short-lived HOC(O)O intermediate. The dynamics results show that only the addition mechanism is important under the conditions considered here. The lifetime of the HOC(O)O complex is predicted to be 172+/-15 fs. This is typical of a direct and fast radical-radical reaction. At room temperature, the calculated thermal rate coefficient is 1.44 x 10(-11) cm(3) mol(-1) s(-1) and its temperature dependence is rather weak. The two kinds of reactive trajectories are illustrated in detail.
采用基于缩放全相关UCCD/D95(d,p)方法的直接从头算动力学方法研究了HOCO与O原子的反应。从头算计算指出了O+HOCO→OH+CO2反应的两种可能反应机制。它们是直接氢提取和通过短寿命HOC(O)O中间体的氧加成反应。动力学结果表明，在此处考虑的条件下，只有加成机制是重要的。预测HOC(O)O络合物的寿命为172±15 fs。这是典型的直接快速自由基-自由基反应。在室温下，计算得到的热速率系数为1.44×10^(-11) cm³ mol⁻¹ s⁻¹，其温度依赖性相当弱。详细说明了两种反应轨迹。
