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F+H2O→HF+OH反应的高精度速率常数的计算研究
李 军*
作者单位E-mail
李 军* 重庆大学化学化工学院重庆 401331 jli15@cqu.edu.cn 
摘要:
F+H2O→HF+OH是四原子反应的典型代表,并在环境和天体化学中扮演着重要角色. 基于全维势能面,本文采用环-聚合分子动力学(RPMD)方法计算了该反应的速率常数. 该势能面可以重现高精度理论化学水平(FPA和HEAT)上得到的反应能垒和放热数据,它是目前该体系的最准确势能面. RPMD方法重现了之前半经典过渡态理论结合两维主方程得到的速率常数,二者都与实验结果高度吻合. RPMD方法可以高效可靠地考虑量子效应,如量子隧穿和零点能效应等. 另外,RPMD计算结果随珠子数量增加收敛较快,这些都与之前RPMD的诸多计算应用发现的结论一致.
关键词:  速率常数,环-聚合分子动力学,量子隧穿
DOI:10.1063/1674-0068/cjcp1808186
分类号:
基金项目:
Ring-Polymer Molecular Dynamics Studies of Thermal Rate Coefficients for Reaction F+H2O→HF+OH
Jun Li*
Abstract:
The prototype tetra-atomic reaction F+H2O→HF+OH plays a significant role in both atmospheric and astronomical chemistry. In this work, thermal rate coefficients of this reaction are determined with the ring polymer molecular dynamics (RPMD) method on a full-dimensional potential energy surface (PES). This PES is the most accurate one for the title reaction, as demonstrated by the correct barrier height and reaction energy, compared to the benchmark calculations by the focal point analysis and the high accuracy extrapolated ab initio thermochemistry methods. The RPMD rate coefficients are in excellent agreement with those calculated by the semiclassical transition state theory and a two-dimensional master equation technique, and some experimental measurements. As has been found in many RPMD applications, quantum effects, including tunneling and zeropoint energy effects, can be efficiently and effectively captured by the RPMD method. In addition, the convergence of the results with respect to the number of beads is rapid, which is also consistent with previous RPMD applications.
Key words:  Rate coefficients, Ring polymer molecular dynamics, Quantum tunneling