Understanding the influence of different forms of energy (eg, translational, vibrational, rotational) on chemical reactions is a key goal and great challenge in physical chemistry. Very recently, we proposed a new approach to obtain state‐selective cross sections that approximately include quantum effects such as zero‐point energy and tunneling. The method is a combination of the widely used quasiclassical trajectory approach (QCT) and the ring polymer molecular dynamics method and thus is numerically very efficient and easily employed. Here, we present a detailed description of the method and exhaustive tests of its accuracy and applicability. The robustness of the approach is tested, as well as the convergence with the number of beads. The approach is then applied to several prototypical X + H₂(ν = 0, 1), X = Mu, H, D, F, Cl reactions over a wide range of collision energies. Good agreement with rigorous quantum dynamics simulations is found for most cases. Encouraging improvement over QCT results is found for particular cases, while only a small increase in numerical cost is required.

中文翻译：

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环状聚合物分子动力学的状态选择截面

理解不同形式的能量（例如，平移，振动，旋转）对化学反应的影响是物理化学的主要目标和巨大挑战。最近，我们提出了一种新的方法来获得状态选择截面，该截面近似包括量子效应，例如零点能量和隧穿。该方法是广泛使用的准经典轨迹法（QCT）和环状聚合物分子动力学方法的结合，因此在数值上非常有效且易于使用。在这里，我们介绍该方法的详细说明以及其准确性和适用性的详尽测试。测试了该方法的鲁棒性以及与珠子数量的收敛性。然后将该方法应用于几个原型X + H ₂（ν = 0，1），X =在广泛的碰撞能量范围内的Mu，H，D，F，Cl反应。在大多数情况下，可以找到与严格的量子动力学模拟完全一致的方法。对于特殊情况，发现在QCT结果上有令人鼓舞的改进，而数字成本只需要少量增加。