Department of Physical Chemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia.
J Chem Phys. 2013 Aug 14;139(6):064307. doi: 10.1063/1.4817241.
We extend a recently developed wave packet method for computing the state-to-state quantum dynamics of AB + CD → ABC + D reactions [M. T. Cvitaš and S. C. Althorpe, J. Phys. Chem. A 113, 4557 (2009)] to include the Chebyshev propagator. The method uses the further partitioned approach to reactant-product decoupling, which uses artificial decoupling potentials to partition the coordinate space of the reaction into separate reactant, product, and transition-state regions. Separate coordinates and basis sets can then be used that are best adapted to each region. We derive improved Chebyshev partitioning formulas which include Mandelshtam-and-Taylor-type decoupling potentials, and which are essential for the non-unitary discrete variable representations that must be used in 4-atom reactive scattering calculations. Numerical tests on the fully dimensional OH + H2 → H2O + H reaction for J = 0 show that the new version of the method is as efficient as the previously developed split-operator version. The advantages of the Chebyshev propagator (most notably the ease of parallelization for J > 0) can now be fully exploited in state-to-state reactive scattering calculations on 4-atom reactions.
我们将最近开发的用于计算 AB + CD → ABC + D 反应的态态量子动力学的波包方法[M. T. Cvitaš 和 S. C. Althorpe, J. Phys. Chem. A 113, 4557 (2009)]扩展到包括 Chebyshev 传播子。该方法使用进一步的反应物-产物解耦分区方法，该方法使用人为解耦势将反应的坐标空间分为单独的反应物、产物和过渡态区域。然后可以使用最适合每个区域的单独坐标和基集。我们推导出改进的 Chebyshev 分区公式，其中包括 Mandelshtam 和 Taylor 型解耦势，这对于必须用于 4 原子反应散射计算的非单位离散变量表示是必不可少的。对于 J = 0 的完全维度 OH + H2 → H2O + H 反应的数值测试表明，该方法的新版本与之前开发的分裂算符版本一样高效。现在可以在 4 原子反应的态态反应散射计算中充分利用 Chebyshev 传播子的优势（最显著的是对于 J > 0 易于并行化）。
