乙炔基自由基C_2H与氧气反应的密度泛函理论研究  

Theoretical Study on the Reaction of Ethynyl Radical with Oxygen by Density Functional Theory

作　　者：白洪涛[1] 黄旭日[1] 于健康[1] 孙家钟[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：《化学学报》2004年第5期461-466,共6页Acta Chimica Sinica

基　　金：国家自然科学基金 (N0 .2 0 1 0 30 0 3);教育部骨干教师基金;吉林省杰出青年资助项目

摘　　要：应用量子化学从头算和密度泛函理论 (DFT)对C2 H自由基和O2 的反应进行了研究 .在B3LYP/6 3 11G 水平上优化了反应通道上各驻点 (反应物、中间体、过渡态和产物 )的几何构型 ,并计算出它们的振动频率和零点振动能 (ZPVE) .各物种的总能量由CCSD(T) /6 3 11G //B3LYP/6 3 11G 给出 ,并对能量进行了零点能校正 .计算结果表明 ,反应物中自由基C2 H中的边端C进攻O2 形成了中间体 1(HCCOO) ,中间体 1是一个加合产物 .由中间体 1经过不同的反应通道可以生成不同的产物P1(HCO +CO) ,P2 (HCCO +O) ,P3 (CO2 +CH) ,P4(C2 O +OH)和P5( 2CO +H) .反应通道之间存在着竞争机制 .其中P1,P2 是主要产物 ,其次还有一定比例的P5生成 ,而产物P3 ,P4的生成几率较低 .Using the density function theory (DFT) and ab initio calculation, the reaction of ethynyl radical with oxygen was studied. At 6-311G (d,p) level with DFT method, the geometries of all species (reactants, transition states and products) were optimized and the vibration frequencies and zero point vibration energies (ZPVE) were also calculated. All the energies of the species were obtained with the correction of ZPVE at the same base set level with CCSD method. The calculated results suggest that the ethynyl radical attacks the site of O-atom of oxygen to form the I_1, isomer 1 (HCCOO). The I_1 undergoes different channels and can form five products, i.e. P_1 (HCO+CO), P_2 (HCCO+O), P_3 (CO_2+CH), P_4 (C_2O+OH) and P_5 (2CO+H). A notable finding is that the P_1 and P_2 are the main products, and the P_5 is much less competitive, while the P_3 and P_4 are unfeasible due to the potential energy surface (PES). This investigation could excellently explain the experiment of the title reaction.

关 键 词：乙炔基自由基 C2H自由基 氧气 密度泛函理论 量子化学从头算 几何构型 振动频率 零点振动能 反应通道 反应热 

分 类 号：O621.13[理学—有机化学]