物理化学学报 >> 2007, Vol. 23 >> Issue (09): 1360-1364.doi: 10.1016/S1872-1508(07)60072-2

研究论文 上一篇    下一篇

多参考态微扰理论大小一致性的数值研究

陈飞武   

  1. 北京科技大学化学系, 北京 100083
  • 收稿日期:2007-05-15 修回日期:2007-07-13 发布日期:2007-09-06
  • 通讯作者: 陈飞武 E-mail:chenfeiwu@sas.ustb.edu.cn

Numerical Study on the Size Consistency of the Multireference Perturbation Theory

CHEN Fei-Wu   

  1. Department of Chemistry, University of Science and Technology Beijing, Beijing 100083, P. R. China
  • Received:2007-05-15 Revised:2007-07-13 Published:2007-09-06
  • Contact: CHEN Fei-Wu E-mail:chenfeiwu@sas.ustb.edu.cn

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摘要： 采用由H2、He 和LiH分别组成的三个超分子系列, 从数值的角度研究了多参考态微扰理论和单双重激发的多参考态组态相互作用(MRSDCI)的大小一致性. 首先在模型空间中进行一个小的完全组态相互作用计算, 然后进行多参考态微扰计算. 数值结果显示, 对这三个模型体系, 我们以前提出的多参考态二级微扰公式是完全大小一致的. 和MRSDCI结果比较, 我们也对它的计算精度进行了讨论. 另外, 还对两组多参考态微扰理论的二级和三级计算结果以及MRSDCI的计算结果的大小一致性误差进行了研究和比较.

关键词: 大小一致性, 多参考态微扰理论, 数值研究

Abstract: The size consistency of the multireference perturbation theory and multireference singly-excited and doubly-excited configuration interaction (MRSDCI) was investigated numerically with three super-molecular models composed of H2, He, and LiH monomers separated by a large distance. A small full configuration interaction was performed first over the model space and then multireference perturbation calculations were carried out. Numerical results demonstrated that the previously derived size consistent multireference second-order perturbation theory was size consistent with respect to the above three super-molecules. Its accuracy relative to the full configuration interaction (CI) was also discussed. Size consistent error of two sets of the multireference second-order and third-order perturbation theories as well as MRSDCI were studied and compared.

Key words: Size consistency, Multireference perturbation theory, Numerical study