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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Glycolaldehyde plus OH gas phase reaction: A quantum chemistry divided by CVT/SCT approach
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Glycolaldehyde plus OH gas phase reaction: A quantum chemistry divided by CVT/SCT approach

机译：乙醇醛与OH气相反应：通过CVT / SCT方法划分的量子化学

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We present a theoretical Study of the mechanism and kinetics of the OH hydrogen abstraction from glycolaldehyde. Optimum geometries. frequencies. and gradients have been computed at the BH and HLYP/ 6-311++G(d,p) level of theory for all stationary points, as well as for additional points along the minimum energy path (MEP). Enemies are obtained by single-point calculations at the above geometries using CCSD- (T)/6-311++G(d,p) to produce the potential energy surface. The rate coefficients are calculated for the temperature range 200-500 K by using canonical variational theory (CVT) with Small-curvature tunneling (SCT) corrections. Our analysis suggests a stepwise mechanism involving the formation of a reactant complex in the entrance channel and a product complex in the exit channel, for all the modeled paths. The overall agreement between the calculated and experimental kinetic data that are available at 298 K is very good. This agreement supports the reliability of the parameters obtained for the temperature dependence of the glycolaldehyde + OH reaction. The expressions that best describe the studied reaction are k(overall) = 7.76 x 10(-13) e(1328/RT) cm(3.)molecule(-1.)s(-1) and k(overall) = 1.09 x 10(-21)T(3.03) e(3187/RT) cm(3) molecule(-1) s(-1). for the Arrhenius and Kooij approaches, respectively. The predicted activation energy is (-1.36 +/- 0.03) kcal/mol. at about 298 K. The agreement between the calculated and experimental branching ratios is better than 10%. The intramolecular hydrogen bond in OO-s-cis glycolaldehyde is found to be responsible for the discrepancies between SAR and experimental rate coefficients.
机译：我们提出了从乙醇醛提取OH氢的机理和动力学的理论研究。最佳几何形状。频率。对于所有固定点以及沿最小能量路径（MEP）的其他点，已经在BH和HLYP / 6-311 ++ G（d，p）的理论水平上计算了梯度和梯度。通过使用CCSD-（T）/ 6-311 ++ G（d，p）在上述几何形状上进行单点计算来获得敌人，以产生势能面。通过使用具有小曲率隧道效应（SCT）校正的规范变分理论（CVT），可以计算200-500 K温度范围内的速率系数。我们的分析表明，对于所有建模路径，逐步机制都涉及在入口通道中形成反应物络合物和在出口通道中形成产物络合物。在298 K下可获得的计算和实验动力学数据之间的总体一致性非常好。该协议支持了对于乙醇醛+ OH反应的温度依赖性所获得的参数的可靠性。最能描述所研究反应的表达式是k（整体）= 7.76 x 10（-13）e（1328 / RT）cm（3。）分子（-1。）s（-1）和k（整体）= 1.09 x 10（-21）T（3.03）e（3187 / RT）cm（3）分子（-1）s（-1）。阿雷尼乌斯（Arrhenius）和库伊（Kooij）进近。预测的活化能为（-1.36 +/- 0.03）kcal / mol。在大约298 K时。计算和实验分支比之间的一致性优于10％。发现OO-s-顺式乙醇醛中的分子内氢键是SAR与实验速率系数之间差异的原因。

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