自由基CH和CH_2的基态结构与势能函数  

Structure and potential energy function of ground-state CH and CH_2 free radical

作　　者：孙金锋[1] 王爱华[1] 施德恒[1] 朱遵略[1] 

机构地区：[1]河南师范大学物理与信息工程学院,新乡453007

出　　处：《原子与分子物理学报》2008年第2期267-273,共7页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(10574039)

摘　　要：选用CCSD(T)/Aug-cc-PV5Z方法,对CH分子基态的平衡几何进行了优化计算,得到了对应的计算结果.运用含微扰的二次组态相关方法,选用CC-PV5Z基组对CH2分子的基态平衡几何进行了优化计算,得到的结果是:该分子的基态结构为C2v构型,电子态为X3B1,平衡核间距RCH=0 .10769 nm,键角∠HCH=133 .707°,离解能De=5 .3277 eV,基态振动频率ν1( a1)=1094 .24 cm-1,ν2( a1)=3144 .91 cm-1,ν3( b2)=3373 .63 cm-1.采用多体项展式理论推导了CH2分子基态的解析势能函数,其等值势能图准确再现了CH2分子的结构特征及其势阱深度与位置.在分析讨论势能面的静态特征时,得到了CH+H→CH2反应中存在的两个对称鞍点,其活化能为0 .13124 kJ/mol .Employing the CCSD（T） method and the correlation-consistent valence quintuple zeta basis set,Aug-cc-PV5Z,we calculate the ground-state interaction potential of CH.The ground-state interaction potential of CH2 is calculated using the QCISD（T） method and the correlation-consistent valence polarized quintuple zeta basis set,CC-PV5Z.The results show that the ground state of CH2 radical has C2v symmetry.The equilibrium parameters and the harmonic frequencies are of RCH=0.10769 nm,∠HCH=133.707°,De=5.3277 eV,ν1（a1）=1094.24 cm^-1,ν2（a1）= 3144.91 cm^-1 and ν3（b2）=3373.63 cm^-1,respectively.The potential energy function of CH2 is derived from the many-body expansion theory.The potential energy function of CH2 radical describes correctly the configuration and the ground-state dissociation energy.Based on the potential energy function,molecular reaction kinetics of CH＋H→CH2 is discussed briefly.

关 键 词：CH2 CH MURRELL-SORBIE函数 多体项展式理论 解析势能函数 

分 类 号：O561.1[理学—原子与分子物理]