标题： 密度泛函理论中的自旋迁移：能量、势和密度视角 显示英文标题

标题： Spin migration in density functional theory: energy, potential and density perspectives

摘要： 自旋是任何多电子系统的基本属性。 密度泛函理论在改变自旋的同时准确预测系统物理性质的能力，对于描述磁性材料和高自旋分子、自旋翻转、磁化和去磁化过程至关重要。 在密度泛函理论中，当使用各种交换相关近似时，能量对自旋的精确依赖关系通常偏离精确的常数或分段线性行为，这直接与强（静态）关联问题相关，并对分子解离的描述构成挑战。 在本文中，我们研究了不同原子系统中能量、前沿Kohn-Sham（KS）轨道、KS势和电子密度相对于分数自旋的行为。 我们分析了五个标准的交换相关泛函，并发现偏离预期精确结果的三种主要情形。 我们明确识别出在精确交换和杂化泛函中，自旋变化时前沿轨道能量的跳跃，以及相应KS势中的平台区。 我们的结果对于从新角度评估现有近似的质量以及开发对磁性特性敏感的先进泛函具有重要意义。 显示英文摘要

摘要： Spin is a fundamental property of any many-electron system. The ability of density functional theory to accurately predict the physical properties of a system, while varying its spin, is crucial for describing magnetic materials and high-spin molecules, spin flip, magnetization and demagnetization processes. Within density functional theory, when using various exchange-correlation approximations, the exact dependence of the energy on the spin often deviates from the exact constant or piecewise-linear behavior, which is directly related to the problem of strong (static) correlation and challenges the description of molecular dissociation. In this paper, we study the behavior of the energy, the frontier Kohn-Sham (KS) orbitals, the KS potentials and the electron density, with respect to fractional spin, in different atomic systems. We analyze five standard exchange-correlation functionals and find three main scenarios of deviation from the expected exact results. We clearly recognize a jump in the frontier orbital energies upon spin variation in the exact exchange and in hybrid functionals, and the related plateau in the corresponding KS potential. Our results are instrumental for the assessment of the quality of existing approximations from a new perspective and for the development of advanced functionals with sensitivity to magnetic properties.