Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain.
Phys Chem Chem Phys. 2012 Mar 14;14(10):3346-59. doi: 10.1039/c2cp23479c. Epub 2012 Feb 2.
An extensive set of experimental measurements on the dynamics of the H(+) + D(2) and D(+) + H(2) ion-molecule reactions is compared with the results of quantum mechanical (QM), quasiclassical trajectory (QCT), and statistical quasiclassical trajectory (SQCT) calculations. The dynamical observables considered include specific rate coefficients as a function of the translational energy, E(T), thermal rate coefficients in the 100-500 K temperature range. In addition, kinetic energy spectra (KES) of the D(+) ions reactively scattered in H(+) + D(2) collisions are also presented for translational energies between 0.4 eV and 2.0 eV. For the two reactions, the best global agreement between experiment and theory over the whole energy range corresponds to the QCT calculations using a gaussian binning (GB) procedure, which gives more weight to trajectories whose product vibrational action is closer to the actual integer QM values. The QM calculations also perform well, although somewhat worse over the more limited range of translational energies where they are available (E(T) < 0.6 eV and E(T) < 0.2 eV for the H(+) + D(2) and D(+) + H(2) reactions, respectively). The worst agreement is obtained with the SQCT method, which is only adequate for low translational energies. The comparison between theory and experiment also suggests that the most reliable rate coefficient measurements are those obtained with the merged beams technique. It is worth noting that none of the theoretical approaches can account satisfactorily for the experimental specific rate coefficients of H(+) + D(2) for E(T)≤ 0.2 eV although there is a considerable scatter in the existing measurements. On the whole, the best agreement with the experimental laboratory KES is obtained with the simulations carried out using the state resolved differential cross sections (DCSs) calculated with the QCT-GB method, which seems to account for most of the observed features. In contrast, the simulations with the SQCT data predict kinetic energy spectra (KES) considerably cooler than those experimentally determined.
对 H(+) + D(2) 和 D(+) + H(2) 离子分子反应动力学进行了广泛的实验测量，并将结果与量子力学 (QM)、准经典轨迹 (QCT) 和统计准经典轨迹 (SQCT) 计算进行了比较。所考虑的动力学观测值包括特定速率系数作为平移能 E(T) 的函数，在 100-500 K 温度范围内的热速率系数。此外，还给出了 H(+) + D(2) 碰撞中 D(+) 离子反应散射的动能谱 (KES)，平移能在 0.4 eV 到 2.0 eV 之间。对于这两个反应，在整个能量范围内，实验与理论之间的最佳总体一致性对应于使用高斯分箱 (GB) 程序的 QCT 计算，该程序更重视产物振动作用更接近实际整数 QM 值的轨迹。QM 计算也表现良好，尽管在它们可用的更有限的平移能范围内稍差 (对于 H(+) + D(2) 和 D(+) + H(2) 反应，分别为 E(T) < 0.6 eV 和 E(T) < 0.2 eV)。与 SQCT 方法的一致性最差，该方法仅适用于低平移能。理论与实验的比较还表明，最可靠的速率系数测量是使用合并束技术获得的测量值。值得注意的是，尽管现有的测量值存在很大的分散性，但没有一种理论方法可以令人满意地解释 H(+) + D(2) 在 E(T)≤0.2 eV 时的实验特定速率系数。总的来说，与实验实验室 KES 最一致的是使用 QCT-GB 方法计算的状态分辨微分截面 (DCS) 进行的模拟，该模拟似乎解释了大部分观察到的特征。相比之下，使用 SQCT 数据进行的模拟预测的动能谱 (KES) 比实验确定的要冷得多。
