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Development of ReaxFF SFOH Force Field for SF 6 ‐H 2 O/O 2 Hybrid System Based on Synergetic Optimization by CMA‐ES and MC Methodology
Author(s) -
Liu Heng,
Wang Jingrui,
Li Qingmin,
Haddad A. Manu
Publication year - 2021
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202101174
Subject(s) - reaxff , force field (fiction) , molecular dynamics , chemistry , monte carlo method , computational chemistry , materials science , physics , mathematics , quantum mechanics , interatomic potential , statistics
The reactive force field (ReaxFF) based molecular dynamic (MD) simulation provides a new perspective for studying the microscopic decomposition mechanism of sulfur hexafluoride (SF 6 ) under fault conditions. Since none of the published ReaxFF force fields contains proper interaction relationship between S, F, O and H elements, the development of ReaxFF parameters for SF 6 ‐H 2 O/O 2 hybrid system is urgently needed. In this work, a universal and efficient covariance matrix adaptation evolutionary strategy (CMA‐ES) and Monte‐Carlo FF (MCFF) synergetic (CMS) optimization strategy for ReaxFF parameter is proposed. The optimization results for two representative force fields (disulfide and silica) from literature show that under the same number of evaluations, the CMS optimization strategy significantly reduces the optimization error by 22.08 % (disulfide) and 10.3 % (silica) respectively. By applying CMS strategy, the ReaxFF SFOH force field for SF 6 ‐H 2 O/O 2 hybrid system is efficiently obtained. Through multi‐dimensional force field performance verification, we find that the bond length calculation error between ReaxFF and density functional theory (DFT) calculation results is mainly concentrated within ±0.05 Å, and the bond angle error is mostly within ±5°. In addition, the trends of relative energy changes during chemical reaction processes calculated by ReaxFF are basically consistent with the DFT results. This work lays a solid foundation for the in‐depth study of the microscopic influence mechanism of trace H 2 O and trace O 2 in the decomposition process of SF 6 .