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...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(^3P)+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.展开更多
The dynamics of the ground-state reaction of CH4＋ O（~3P） → CH3（ν = 0） ＋ OH（ ν= 0） have attracted a great deal of attention both theoretically and experimentally. This rapid communication represents extensiv...The dynamics of the ground-state reaction of CH4＋ O（~3P） → CH3（ν = 0） ＋ OH（ ν= 0） have attracted a great deal of attention both theoretically and experimentally. This rapid communication represents extensive quasi-classical trajectory calculations of the vibrational distributions on a unique full-dimensional ab initio potential energy surface for the title reaction, at the collision energy of relevance to previous crossed molecular beam experiments. The surface is constructed using the all electrons coupled-cluster singles and doubles approach plus quasi-perturbative triple excitations with optimized basis sets. A modified Shepard interpolation method is also employed for the construction. Good agreement between our calculations and the available experimental results has been achieved, opening the door for accurate dynamics on this surface.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51574016)and completed while the author was in residence at UNSW,Australia supported by the International Cooperation Training Program for Innovative Talents of USTB.
文摘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(^3P)+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.
基金supported by the National Natural Science Foundation of China(Grant Nos.51574016 and 51604018)
文摘The dynamics of the ground-state reaction of CH4＋ O（~3P） → CH3（ν = 0） ＋ OH（ ν= 0） have attracted a great deal of attention both theoretically and experimentally. This rapid communication represents extensive quasi-classical trajectory calculations of the vibrational distributions on a unique full-dimensional ab initio potential energy surface for the title reaction, at the collision energy of relevance to previous crossed molecular beam experiments. The surface is constructed using the all electrons coupled-cluster singles and doubles approach plus quasi-perturbative triple excitations with optimized basis sets. A modified Shepard interpolation method is also employed for the construction. Good agreement between our calculations and the available experimental results has been achieved, opening the door for accurate dynamics on this surface.
