Yu Hua-Gen, Francisco Joseph S, Muckerman James T
Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
J Chem Phys. 2008 Aug 14;129(6):064301. doi: 10.1063/1.2965523.
The reaction of Cl with HOCO has been examined using the coupled-cluster method to locate and optimize the critical points on the ground-state potential energy surface. The results show that the reaction produces the HCl and CO(2) products as experimentally observed. The reaction occurs via a HOC(O)Cl intermediate with an estimated heat of formation of -97.8+/-2.0 kcal/mol. A direct ab initio dynamics method has been used to provide insight into the reaction mechanisms and to determine the thermal rate coefficients in the temperature range of 200-600 K. At room temperature, the thermal rate coefficient is predicted to be 3.0x10(-11) cm(3) molecule(-1) s(-1) with an activation energy of -0.2 kcal/mol. Two kinds of reactive trajectories are found. One kind proceeds through short-lived HOC(O)Cl complexes with a lifetime of 310 fs while the other kind occurs via longer-lived intermediates with a lifetime of 1.9 ps.
已使用耦合簇方法研究了Cl与HOCO的反应，以定位和优化基态势能面上的临界点。结果表明，该反应如实验观察到的那样生成HCl和CO₂产物。反应通过HOC(O)Cl中间体发生，其估计生成热为-97.8±2.0 kcal/mol。已使用直接从头算动力学方法来深入了解反应机理，并确定200 - 600 K温度范围内的热速率系数。在室温下，预测热速率系数为3.0×10⁻¹¹ cm³·分子⁻¹·s⁻¹，活化能为-0.2 kcal/mol。发现了两种反应轨迹。一种通过寿命为310 fs的短寿命HOC(O)Cl络合物进行，而另一种通过寿命为1.9 ps的长寿命中间体发生。
