物理化学学报 >> 2003, Vol. 19 >> Issue (07): 626-629.doi: 10.3866/PKU.WHXB20030712

研究论文 上一篇    下一篇

CH3(2A′)自由基与臭氧反应机理的量子化学研究

李来才;田安民   

  1. 四川师范大学化学系,成都 610066; 1四川大学化学系, 成都 610065
  • 收稿日期:2002-12-16 修回日期:2003-02-21 发布日期:2003-07-15
  • 通讯作者: 李来才 E-mail:liline33@sohu.com

Quantum Study on the Reaction Mechanism of CH3(2A′) Radicals with Ozone Reaction

Li Lai-Cai;Tian An-Min   

  1. Department of Chemistry ,Sichuan Normal University, Chengdu 610066; 1Department of Chemistry, Sichuan University, Chengdu 610065
  • Received:2002-12-16 Revised:2003-02-21 Published:2003-07-15
  • Contact: Li Lai-Cai E-mail:liline33@sohu.com

摘要: 用量子化学UMP2方法,在6-311++G**基组水平上研究了CH3(2A′)自由基与臭氧反应机理,全参数优化了反应过程中反应物、中间体、过渡态和产物的几何构型,在UQCISD(T)/6-311++G**水平上计算了它们的能量;并对它们进行了振动分析,以确定中间体和过渡态的真实性;同时应用经典过渡态理论计算了反应的速率常数,并与实验值进行了比较, CH3自由基与臭氧反应速率常数的理论计算结果为: 4.73×10-14 cm3•molecule-1•s-1,与实验报导的结果(k=2.52×10-14 cm3•molecule-1•s-1)很接近,同时发现CH3(2A′)自由基与O3的反应是强放热反应.

关键词: 反应机理, 过渡态, 反应通道, 从头算

Abstract: The geometries of reactants, transition states, intermediates and products on the reaction of CH3(2A′)+O3 have been optimized at the UMP2/6-31++G** level. The transition states and intermediates of the reactions were verified by frequency analysis. The relative single-point energies were further calculated at the UQCISD(T)/6-311++G** level, based on the UMP2/6-311++G** optimized structures. The zero point energy (ZPE) corrections and reaction’s rate constants were also obtained. We used the classic transition state theory to compute the rate constants of the CH3(2A′)+O3 reaction (k=4.73×10-14 cm3•molecule-1•s-1). Compared with the experimental values (k=2.52×10-14 cm3•molecule-1•s-1), our calculated result is in good agreement with experimental datum.

Key words: Reaction mechanism, Transition state, Reaction channel, Ab initio