Luckhaus David
Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, B.C., Canada.
Phys Chem Chem Phys. 2008 Nov 7;10(41):6215-22. doi: 10.1039/b809361j. Epub 2008 Sep 9.
The reaction path Hamiltonian [J. Chem. Phys., 1980, 72(1), 99] has found few if any successful applications to the explicit treatment of hydrogen tunnelling dynamics in the limit of large path curvature which is typical for hydrogen exchange tunnelling. I argue hat this is due to fundamental limitations of the reaction path formulation. A two-dimensional model mimicking the intramolecular hydrogen transfer in malonaldehyde shows that commonly used approximations can produce misleading results. As a solution to the problem I propose a non-orthogonal representation of the Hamiltonian in terms of local harmonic oscillators distributed along the reaction path. In contrast to the usual reaction path Hamiltonian it has an exact variational limit for all curvatures. This distributed harmonic oscillator approach has the added advantages of stability against variations of the reaction path as well as the ability to treat bifurcating paths.
反应路径哈密顿量[《化学物理杂志》，1980年，72(1)，99]在处理大路径曲率极限下氢隧穿动力学的显式问题时，几乎没有（如果有的话）成功应用，而大路径曲率是氢交换隧穿的典型特征。我认为这是由于反应路径公式的基本局限性。一个模拟丙二醛分子内氢转移的二维模型表明，常用的近似方法可能会产生误导性结果。作为该问题的解决方案，我提出了一种基于沿反应路径分布的局部谐振子的哈密顿量非正交表示。与通常的反应路径哈密顿量不同，它对于所有曲率都有精确的变分极限。这种分布式谐振子方法具有对反应路径变化稳定以及能够处理分支路径的额外优点。
