Reaction dynamics with the multi-layer multi-configurational time-dependent Hartree approach: H + CH4 → H2 + CH3 rate constants for different potentials.
Reaction dynamics with the multi-layer multi-configurational time-dependent Hartree approach: H + CH4 → H2 + CH3 rate constants for different potentials.
复制标题
DOI：
10.1063/1.4772585
复制
发表时间：
2012-12
期刊：
影响因子：
--
通讯作者：
R. Welsch;U. Manthe
中科院分区：
文献类型：
--
作者：
R. Welsch;U. Manthe
将多组态含时Hartree方法（MCTDH）的多层扩展应用于基元双分子化学反应的研究。利用通量关联函数和量子过渡态概念计算了H + CH（4）→ H（2）+ CH（3）反应的累积反应几率和热速率常数。不同的坐标系和势能面（PES）进行了研究。研究了不同层数的收敛特性，并将多层MCTDH方法的效率与标准MCTDH方法进行了比较。据发现，多层的方法可以减少一个数量级以上的数值努力。由多层MCTDH方法产生的提高的效率对于最近的全局H + CH（4）→ H（2）+ CH（3）PES的量子动力学计算是至关重要的，例如，ZBB 3-PES [Z. Xie，J. M. Bowman和X. Zhang，J.Chem.Phys.125，133120（2006）]，其基于置换不变多项式，其在数值上比早期PES要求更高。结果表明，准确描述所有过渡态的频率是重要的，以获得准确的热速率常数。
The multi-layer extension of the multi-configurational time-dependent Hartree (MCTDH) approach is applied to the investigation of elementary bimolecular chemical reactions. Cumulative reaction probabilities and thermal rate constants of the H + CH(4) → H(2) + CH(3) reaction are calculated using flux correlation functions and the quantum transition state concept. Different coordinate systems and potential energy surfaces (PESs) are studied. The convergence properties of different layerings are investigated and the efficiency of multi-layer MCTDH approach is compared to the standard MCTDH approach. It is found that the multi-layer approach can decrease the numerical effort by more than an order of magnitude. The increased efficiency resulting from the multi-layer MCTDH approach is crucial for quantum dynamical calculations on recent global H + CH(4) → H(2) + CH(3) PESs, e.g., the ZBB3-PES [Z. Xie, J. M. Bowman, and X. Zhang, J. Chem. Phys. 125, 133120 (2006)] based on permutational invariant polynomials, which are numerically more demanding than earlier PESs. The results indicate that an accurate description of all transition state frequencies is important to obtain accurate thermal rate constants.