DNA碱基的电子相关效应

The Effect of Electron Correlation of DNA Bases

分别在Hartree-Fock和二级Moller-Pleset微扰理论MP2的电子相关校正水平,用6-31G基函数对四种DNA碱基胞嘧啶、胸腺嘧啶、鸟嘌呤和腺嘌呤的能量、偶极矩、电荷分布和分子静电势等性质进行了系统的从头计算研究.其中,采用Z矢量方法在波函数中加入MP2级别的电子相关校正;分别用Mulliken布居分析、静电势导出电荷CHELPG以及自然布居分析NPA方法计算分子中原子电荷.在上述计算结果的基础上,系统地分析了DNA碱基的电子相关效应.

Ab initio calculations have been carried out at the Hartree - Fock and the second order Moller- Plesset perturbation theory MP2 levels using 6 - 31G* * basis set to determine the molecular energies, dipole moments, atomic charges and electrostatic potential distributions of DNA bases, adenine, cytosine, guanine and thymine. The electron correlation is included in the wave functions at the MP2 level using the Z - vector method. The atomic charges were obtained by the Mulliken population analysis, Breneman's electrostatic potential derived atomic charges CHELPG model and Reed - Weinhold's natural population analysis NPA. Based on these results, the effect of elecetron correlation of the DNA bases were systematically analysed in this article.