Reaction Dynamics of CH3 + HBr → CH4 + Br at 150-1000 K

Bulletin of the Korean chemical society

Jongbaik Ree¹  Yoo Hang Kim¹  Hyung Kyu Shin¹ 

关键词: Complex-mode reaction;    Tunneling;    Trajectory;    Rate constant;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

The kinetics of the radical-polar molecule reaction CH3 + HBr → CH4 + Br has been studied at temperatures between 150 and 1000 K using classical dynamics procedures. Potential energy surfaces constructed using analytical forms of inter- and intramolecular interaction energies show a shallow well and barrier in the entrance channel, which affect the collision dynamics at low temperatures. Different collision models are used to distinguish the reaction occurring at low- and high-temperature regions. The reaction proceeds rapidly via a complex-mode mechanism below room temperature showing strong negative temperature dependence, where the effects of molecular attraction, H-atom tunneling and recrossing of collision complexes are found to be important. The temperature dependence of the rate constant between 400 and 1000 K is positive, the values increasing in accordance with the increase of the mean speed of collision. The rate constant varies from 7.6 × 10−12 at 150 K to 3.7 × 10−12 at 1000 K via a minimum value of 2.5 × 10−12 cm3 molecule−1 s−1 at 400 K.

【 授权许可】

Unknown