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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Quasiclassical trajectory study of H+SiH_4 reactions in full-dimensionality reveals atomic-level mechanisms
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Quasiclassical trajectory study of H+SiH_4 reactions in full-dimensionality reveals atomic-level mechanisms

机译：H + SiH_4反应的全尺度准经典轨迹研究揭示了原子级机理

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摘要

This work elucidates new atomic-level mechanisms that may be common in a range of chemical reactions, and our findings are important for the understanding of the nature of polyatomic abstraction and exchange reactions. A global 12-dimensional ab initio potential energy surface (PES), which describes both H+SiH_4 abstraction and exchange reactions is constructed, based on the modified Shep-ard interpolation method and UCCSD(T)/cc-pVQZ energy calculations at 4,015 geometries. This PES has a classical barrier height of 5.35 kcal/mol for abstraction (our best estimate is 5.35 ± 0.15 kcal/mol from extensive ab initio calculations), and an exothermicity of -13.12 kcal/mol, in excellent agreement with experiment. Quasiclassical trajectory calculations or' this new PES reveal interesting features of detailed dynamical quantities and underlying new mechanisms. Our calculated product angular distributions for exchange are in the forward hemisphere with a tail sideways, and are attributed to the combination of three mechanisms: inversion, torsion-tilt, and side-inversion. With increase of collision energy our calculated angular distributions for abstraction first peak at backward scattering and then shift toward smaller scattering angles, which is explained by a competition between rebound and stripping mechanisms; here stripping is seen at much lower energies, but is conceptually similar to what was observed in the reaction of H+CD_4 by Zare and coworkers [Camden JP, et al. (2005) J Am Chem Soc 127:11898-11899]. Each of these atomic-level mechanisms is confirmed by direct examination of trajectories, and two of them (torsion-tilt and side-inversion) are proposed and designated in this work.
机译：这项工作阐明了在一系列化学反应中可能常见的新原子级机理，我们的发现对于理解多原子抽象和交换反应的性质非常重要。基于修改后的Shep-ard插值方法和4,015个几何的UCCSD（T）/ cc-pVQZ能量计算，构建了一个描述H + SiH_4抽象和交换反应的全局12维从头算势表面（PES） 。该PES的抽象势垒高度为5.35 kcal / mol（根据广泛的从头算计算，我们的最佳估计为5.35±0.15 kcal / mol），放热值为-13.12 kcal / mol，与实验非常吻合。准经典轨迹计算或这种新的PES揭示了详细的动力学量和潜在的新机制的有趣特征。我们计算出的交换产品角分布在前半球中，尾部在侧面，并且归因于以下三种机制的组合：反转，扭转倾斜和侧面反转。随着碰撞能量的增加，我们计算出的抽象角度分布首先在向后散射处达到峰值，然后向较小的散射角偏移，这可以通过回弹和剥离机制之间的竞争来解释。在这里，汽提被认为是在低得多的能量下进行的，但是从概念上讲，它与扎雷及其同事在H + CD_4的反应中观察到的相似[Camden JP，et al.。 （2005）J Am Chem Soc 127：11898-11899]。这些原子级机制中的每一种都可以通过直接检查轨迹来确定，并且在这项工作中提出并指定了其中两种（扭转倾斜和侧面反转）。

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  • 作者

    Jianwei Cao; Zhijun Zhang; Chunfang Zhang; Kun Liu; Manhui Wang; Wensheng Bian;

  • 作者单位

    Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China;

    Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China;

    Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China;

    Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China;

    Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China;

    Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China;

  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    potential energy surface; reaction dynamics;

    机译：势能面反应动力学;

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