Evaluation of 〈S2〉 in restricted, unrestricted Hartree–Fock, and density functional based theories
Evaluation of 〈S2〉 in restricted, unrestricted Hartree–Fock, and density functional based theories
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在受限、非受限 Hartree-Fock 和基于密度泛函的理论中评估<S2>
DOI：
10.1063/1.468585
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发表时间：
1995
影响因子：
4.4
通讯作者：
V. H. Smith
中科院分区：
文献类型：
--
作者：
Jiahu Wang;A. Becke;V. H. Smith
给出了用两粒子密度矩阵计算< S2 >的一个简单公式。讨论了形式主义在受限开壳Hartree-Fock （ROHF）、无限制HF （UHF）和密度泛函（DFT）理论中的实现。给出了基于超高频的方法中控制非零S2矩阵元素的规则。从非常简单的密度泛函模型中给出了< S2 >在几个原子和自由基体系中的进一步例子。
A simple formalism for the evaluation of 〈S2〉 in terms of the two‐particle density matrix is presented. The implementation of the formalism in the restricted open‐shell Hartree–Fock (ROHF), unrestricted HF (UHF) and density functional (DFT) based theories is discussed. Rules governing the nonzero S2 matrix elements in the UHF based methods are presented. Further examples are given of 〈S2〉 in several atomic and radical systems from very simple density functional models.