Counter-propagating wave packets in the quantum transition state approach to reactive scattering.
Counter-propagating wave packets in the quantum transition state approach to reactive scattering.
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DOI：
10.1063/1.5097997
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发表时间：
2019-05
期刊：
影响因子：
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通讯作者：
Bin Zhao;U. Manthe
中科院分区：
文献类型：
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作者：
Bin Zhao;U. Manthe
量子过渡态的概念提供了一个直观的和数值有效的框架来描述量子态分辨的反应散射和热反应过程。将多组态含时Hartree波包动力学计算与基于通量关联函数的分析相结合，对六个原子反应的初态选择几率和态-态反应几率进行严格的全维计算是可行的.在这些计算中，一组波包产生的过渡态区域，传播到渐近区，并进行分析。在目前的工作中，另一种方法，采用反向传播的波包集。在过渡态区域中开始的传出波包与在反应物（或产物）渐近区域中产生的传入波包相匹配。研究H + CH 4 → H2 + CH 3反应作为一个典型的例子，人们发现，传入的波包可以传播到过渡态区域与较小的数值努力。采用输入和输出波函数的互相关函数，输出波包所需的传播时间，从而整个计算的数值成本可以显着减少。对H + CH 4 → H2 + CH 3反应的初态选择反应几率进行了详细的全维计算。结果表明，使用更短的出射波包传播时间和更少的单粒子函数可以得到收敛的结果。
The quantum transition state concept provides an intuitive and numerically efficient framework for the description of quantum state-resolved reactive scattering and thermal reaction processes. Combining multiconfigurational time-dependent Hartree wave packet dynamics calculations with a flux correlation function based analysis, rigorous full-dimensional calculations of initial state-selected and state-to-state reaction probabilities for six atom reactions are feasible. In these calculations, a set of wave packets is generated in the transition state region, propagated into the asymptotic area, and analyzed. In the present work, an alternative approach which employs counter-propagating sets of wave packets is introduced. Outgoing wave packets started in the transition state region are matched with incoming wave packets generated in the reactant (or product) asymptotic area. Studying the H + CH4 → H2 + CH3 reaction as a prototypical example, one finds that the incoming wave packets can be propagated closely up to the transition state region with minor numerical effort. Employing cross correlation functions of incoming and outgoing wavefunctions, the propagation times required for the outgoing wave packet and thus the numerical costs of the entire calculation can be reduced significantly. Detailed full-dimensional calculations studying initial state-selected reaction probabilities for the H + CH4 → H2 + CH3 reaction are presented to illustrate the new approach. It is found that converged results can be obtained using shorter propagation times of the outgoing wave packets and less single-particle functions.