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为深入系统研究电子相关能计算理论,本文报道在6-311+G~*基组水平用CISD(configuration interaction with singly and doubly excited configurations)方法计算基础体系X(X=Li-Ne,HC,H_2C)对内、对间电子相关能。结果表明不同元素所形成的基态X(X=Li-Ne,HC,H_2C)体系,其价层电子对内、对间相关能的变化较大,它们之间存在着轨道差别,不宜将其相关贡献归为简单的常数。以使用相同理论方法和相同质量基组为前提,电子数直接影响电子对间相关能的大小。对于多电子体系,电子对间相关在总相关中占优势,若忽略则会产生较大误差。
In order to study systematically the theory of electron-related energy calculations, the basic system X (X = Li-Ne, HC, H 2 C ) Internal, inter-related electronic energy. The results show that the ground state X (X = Li-Ne, HC, H 2 C) formed by different elements has a large variation in the correlation energy between the valence pair electrons and the valence electron pair, which is not related to the orbital difference Contributions are grouped into simple constants. Using the same theoretical method and the same basis of mass as the premise, the number of electrons directly affects the size of the electron-pair correlation energy. For multi-electron systems, the correlation between pairs of electrons is dominant in the total correlation, which, if ignored, can result in large errors.