物理化学学报 >> 2010, Vol. 26 >> Issue (09): 2331-2336.doi: 10.3866/PKU.WHXB20100907

化学动力学和分子动态学 上一篇    下一篇

从头算分子动力学研究O-与CH3F反应的产物通道

吴琍霞, 于锋, 刘静, 戴静华, 周晓国, 刘世林   

  1. 合肥微尺度物质科学国家实验室(筹), 中国科学技术大学化学物理系,合肥 230026
  • 收稿日期:2010-04-12 修回日期:2010-05-24 发布日期:2010-09-02
  • 通讯作者: 周晓国 E-mail:xzhou@ustc.edu.cn
  • 基金资助:

    国家自然科学基金(20603033, 10979042)和国家重点基础研究发展规划项目(973) (2007CB815204)资助

Ab initioMolecular Dynamics Investigation on the Production Channels for the Reaction of O- with CH3F

WU Li-Xia, YU Feng, LIU Jing, DAI Jing-Hua, ZHOU Xiao-Guo, LIU Shi-Lin   

  1. Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2010-04-12 Revised:2010-05-24 Published:2010-09-02
  • Contact: ZHOU Xiao-Guo E-mail:xzhou@ustc.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20603033, 10979042) and National Key Basic Research Programof China (973) (2007CB815204).

摘要:

在B3LYP/6-31+G(d,p)理论水平下采用基于波恩-奥本海默近似的从头算分子动力学方法重新研究了O-与CH3F 反应经抽氢生成OH-和生成H2O 的两条产物通道. 反应轨线从反应初始过渡态开始, 采用300 K 时的热取样确定初始条件, 同时为对比不同的初始碰撞平动能条件下产物通道的变化, 分别限定过渡矢量上的能量为2.1、36.8 及62.8 kJ·mol-1进行轨线计算, 所有轨线计算的结果表明抽氢生成OH-的过程始终为主要的产物通道. 我们的计算不仅进一步证实了以往实验的结论, 而且描绘了抽氢生成OH-和生成H2O 这两个产物通道在反应出口势能面上的动态反应路径,更为深刻地揭示了该反应的微观机理.

关键词: 从头算分子动力学, 氧负离子, 氟甲烷, 反应机理, 过渡态

Abstract:

H-atom abstraction and H2O production channels for the reaction of O- with CH3F were reinvestigated using the ab initio molecular dynamics method at the B3LYP/6-31+G(d,p) level of theory and based on the Born-Oppenheimer approximation. The reactive trajectories were initiated at the transition state of H-atom abstraction. Thermal sampling at 300 K was chosen to determine the initial conditions. Additionally, the energies added to the transition vector of the barrier were restricted to 2.1, 36.8, and 62.8 kJ·mol -1, separately, to reveal the impact of different initial collision energies on the reaction pathways. The results of all the trajectory calculations demonstrate that the H-atom abstraction channel is the dominant production channel. Therefore, our calculations are consistent with previous experimental conclusions. Furthermore, the dynamic reaction pathways for H-atom abstraction and the H2O production channels on the exit-channel potential energy surface are described based on our calculations and thus a comprehensive reaction mechanismis revealed at the microscopic level.

Key words: Ab initio molecular dynamics, Atomic oxygen radical anion, Methyl fluoride, Reaction mechanism, Transition state

MSC2000: 

  • O643