通讯：基于高精度势能面的环聚合物分子动力学计算H + CH4 → H2 + CH3反应的速率系数

Communication: Rate coefficients of the H + CH4 → H2 + CH3 reaction from ring polymer molecular dynamics on a highly accurate potential energy surface.

作者信息

Meng Qingyong, Chen Jun, Zhang Dong H

机构信息

State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, 116023 Dalian, China.

出版信息

J Chem Phys. 2015 Sep 14;143(10):101102. doi: 10.1063/1.4930860.

DOI:10.1063/1.4930860

PMID:26373990

Abstract

The ring polymer molecular dynamics (RPMD) calculations are performed to calculate rate constants for the title reaction on the recently constructed potential energy surface based on permutation invariant polynomial (PIP) neural-network (NN) fitting [J. Li et al., J. Chem. Phys. 142, 204302 (2015)]. By inspecting convergence, 16 beads are used in computing free-energy barriers at 300 K ≤ T ≤ 1000 K, while different numbers of beads are used for transmission coefficients. The present RPMD rates are in excellent agreement with quantum rates computed on the same potential energy surface, as well as with the experimental measurements, demonstrating further that the RPMD is capable of producing accurate rates for polyatomic chemical reactions even at rather low temperatures.

摘要

基于置换不变多项式（PIP）神经网络（NN）拟合[J. Li等人，《化学物理杂志》142, 204302 (2015)]，在最近构建的势能面上进行了环聚合物分子动力学（RPMD）计算，以计算标题反应的速率常数。通过检查收敛性，在300 K ≤ T ≤ 1000 K计算自由能垒时使用了16个珠子，而在计算传输系数时使用了不同数量的珠子。目前的RPMD速率与在同一势能面上计算的量子速率以及实验测量结果非常吻合，进一步证明了RPMD即使在相当低的温度下也能够为多原子化学反应产生准确的速率。