Surface for methane combustion: O(3p) + CH4→ OH + CH3

• 作者: Ju-Shi Chen Ya Peng Zhong-An Jiang
• 来源期刊: 中国物理B（英文版）
• 关键词: methane combustion potential energy surface transition state kinetic ab initio electronic structure calculation
• 年，卷（期）: 2020,（7）
• 页码范围: 326-335
• 页数: 10页
• 语种: 英文
• DOI: 10.1088/1674-1056/ab90f5

摘要

Kinetic investigations including quasi-classical trajectory and canonical unified statistical theory method calculations are carried out on a potential energy surface for the hydrogen-abstraction reaction from methane by atom O(3p).The surface is constructed using a modified Shepard interpolation method.The ab initio calculations are performed at the CCSD(T) level.Taking account of the contribution of inner core electrons to electronic correlation interaction in ab initio electronic structure calculations,modified optimized aug-cc-pCVQZ basis sets are applied to the all-electrons calculations.On this potential energy surface,the triplet oxygen atom attacks methane in a near-collinear H-CH3 direction to form a saddle point with barrier height of 13.55 kcal/mol,which plays a key role in the kinetics of the title reaction.For the temperature range of 298-2500 K,our calculated thermal rate constants for the O(3 P) + CH4 → OH + CH3 reaction show good agreement with relevant experimental data.This work provides detailed mechanism of this gas-phase reaction and a theoretical guidance for methane combustion.