CF3CH2CH3＋OH的反应机理及动力学性质的理论研究  

Theoretical Study on the Mechanism and Dynamic of CF_3CH_2CH_3 Reaction with OH Radicals

作　　者：王永霞[1] 高红[1] 王钦[1] 刘靖尧[1] 

机构地区：[1]吉林大学理论化学研究所,理论化学计算国家重点实验室,长春130023

出　　处：《高等学校化学学报》2010年第6期1240-1245,共6页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:20333050,20303007,20973077);教育部新世纪优秀人才支持计划(NCET)资助

摘　　要：采用密度泛函理论BB1K/6-31+G(d,p)计算了反应CF3CH2CH3+OH各反应通道上驻点的稳定结构和振动频率,并分别在BMC-CCSD,MC-QCISD和G3(MP2)水平上进行了单点能校正.运用变分过渡态理论,在BMC-CCSD//BB1K,MC-QCISD//BB1K,G3(MP2)//BB1K以及BB1K水平上计算了各反应通道的速率常数,讨论了—CH2和—CH3基团上H提取通道对总反应的贡献,并与已有实验和理论结果进行了对比.计算结果表明,BMC-CCSD水平上的速率常数与实验测量值符合得很好,进而给出了该水平上反应在200～1000K温度范围内速率常数k(cm3.molecule-1.s-1)的三参数表达式:k=1.90×10-21T3.21exp(-292.62/T).The optimized geometries and frequencies of all the stationary points involved in each reaction channel of the CF3CH2CH3＋OH reaction were calculated at the BB1K/6-31＋G（d,p） level,and the potential energy profile is further refined by single-point energy calculations at the BMC-CCSD,MC-QCISD and G3（MP2） levels.The rate constants of all channels were evaluated by variational transition state theory（VTST） at the BMC-CCSD//BB1K,MC-QCISD//BB1K,G3（MP2）//BB1K and BB1K levels over a wide temperature range of 2001000 K,and the contribution of H-abstraction from the CH2 and CH3 groups to the total reaction was discussed.The present calculations show that the rate constants evaluated at the BMC-CCSD//BB1K level are in excellent agreement with the available experimental values in the measured temperature range.Finally,the three-parameter rate-temperature expression of the total reaction over the whole temperature range 2001000 K was given as k=1.90×10-21T 3.21exp（-292.62/T）.

关 键 词：直接动力学 速率常数 变分过渡态理论 CF3CH2CH3 

分 类 号：O641[理学—物理化学] O643[理学—化学]