论文标题
关于Pons Viver对Löwdin的旋转投影操作员实施的数学讨论
A mathematical discussion of Pons Viver's implementation of Löwdin's spin projection operator
论文作者
论文摘要
最近，以黑盒方式有效处理静态（或强）相关性的分子电子结构理论引起了很多关注。在这些理论中，旋转投影算子用于恢复损坏的对称性滑膜决定因素的自旋对称性。最近，Pons Viver提出了Löwdin的自旋投影操作员的实际和精确实现[Int。 J.量子化学。 119，E25770（2019）]。在本研究中，我们试图为Pons Viver的建议提供数学证明，并显示出建立PONS Viver实施的条件。此外，我们根据公共轨道模型（即，在受限的开放式shell hartree-fock（ROHF）方法中使用的封闭壳轨道（即旋转）扩展的Hartree-fock（EHF）方程（EHF）方程，该方程与Pons Viver与EHF方法组合。
Recently the molecular electronic structure theories for efficiently treating static (or strong) correlation in a black-box manner have attracted much attention. In these theories, a spin projection operator is used to recover the spin symmetry of a broken-symmetry Slater determinant. Very recently, Pons Viver proposed the practical and exact implementation of Löwdin's spin projection operator [Int. J. Quantum Chem. 119, e25770 (2019)]. In the present study, we attempt to supply mathematical proofs to Pons Viver's proposals and show a condition for establishing Pons Viver's implementation. Moreover, we explicitly derive the (spin projected) extended Hartree-Fock (EHF) equations on the basis of the model of common orbitals (i.e., closed-shell orbitals used in the restricted open-shell Hartree-Fock (ROHF) method), which was combined by Pons Viver with the EHF method.
