中文摘要：

采用二阶多参考微扰理论计算了F,Cl,OH,SH,CN,CH2和NH2的电子亲和势.另外,还考察了基函数和完全活性空间大小对电子亲和势精度的影响.通过和CASSCF,CASPT2,CCSD,CCSD（T）,B3LYP,X3LYP,M06,HCTH,TPSS,B97D3,m PW2PLYP和B2PLYP的计算结果比较发现,针对目前所用的基函数,二阶多参考态微扰理论的总体计算效果是最好的.

英文摘要：

Electron affinities of F, Cl, OH, SH, CN, CH2, and NH2 have been computed with the second order multireference perturbation theory. The effects of basis set and size of the complete active space on accuracy of electron affinity have also been investigated. The results are compared with calculations performed with CASSCF, CASPT2, CCSD, CCSD（T）, B3 LYP, X3 LYP, M06, HCTH, TPSS, B97D3,mPW2PLYP, and B2PLYP. The overall performance of the second order multireference perturbation theory is best at the level of basis sets used in this study.