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arXiv 2004.12233physics.chem-phcond-mat.other
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在解决Perdew-Zunger自相互作用修正的Partial的方向上迈出了一步。II。三种近似下能量密度的规范一致性

A Step in the Direction of Resolving the Paradox of Perdew-Zunger Self-interaction Correction. II. Gauge Consistency of the Energy Density at Three Levels of Approximation

Puskar Bhattarai, Kamal Wagle, Chandra Shahi, Yoh Yamamoto, Selim Romero, Biswajit Santra, Rajendra R. Zope, Juan E. Peralta, Koblar A. Jackson, John P. Perdew

摘要:

Perdew-Zunger(PZ)自相互作用修正(SIC)的目的是纠正任何近似的交换相关(xc)能量的密度泛函的单电子极限,而不产生任何修正的确切功能。不幸的是,它破坏了未校正近似泛函的空间缓慢变化的限制,这些泛函通过构造是正确的。正确的极限可以通过在多电子区域局部缩小PZ SIC的能量密度来恢复,但是如果PZ SIC能量密度的自Hartree项和精确自xc项用同一规范表示,则会发现对精确泛函的虚假校正。只有局域密度近似满足能量密度的同规范条件,这解释了为什么最近的局域标度SIC(LSIC)在这里被发现只适用于这种基本近似的原子和分子,而不是更先进的广义梯度近似(GGA)和元GGA,通过简化积分的部分失去了哈特里规范。对于精确的xc泛函,实现Hartree规范的能量密度的变换也可以应用于近似泛函。这样做会导致一个简单的按比例缩小的自相互作用(sdSIC)校正,通常比PZ SIC在许多分子性质(包括平衡键长)的测试中更准确。目前的工作表明,明确的PZ SIC适用于标准泛函在三个层次的近似的最大错误,可以通过恢复其正确的缓慢变化的密度限制。它还证实了这些极限对原子和分子的相关性。

英文摘要:

The Perdew-Zunger(PZ) self-interaction correction (SIC) was designed to correct the one-electron limit of any approximate density functional for the exchange-correlation (xc) energy, while yielding no correction to the exact functional. Unfortunately, it spoils the slowly-varying-in-space limits of the uncorrected approximate functionals, where those functionals are right by construction. The right limits can be restored by locally scaling down the energy density of the PZ SIC in many-electron regions, but then a spurious correction to the exact functional would be found unless the self-Hartree and exact self-xc terms of the PZ SIC energy density were expressed in the same gauge. Only the local density approximation satisfies the same-gauge condition for the energy density, which explains why the recent local-scaling SIC (LSIC) is found here to work excellently for atoms and molecules only with this basic approximation, and not with the more advanced generalized gradient approximations (GGAs) and meta-GGAs, which lose the Hartree gauge via simplifying integrations by parts. The transformation of energy density that achieves the Hartree gauge for the exact xc functional can also be applied to approximate functionals. Doing so leads to a simple scaled-down self-interaction (sdSIC) correction that is typically much more accurate than PZ SIC in tests for many molecular properties (including equilibrium bond lengths). The present work shows unambiguously that the largest errors of PZ SIC applied to standard functionals at three levels of approximation can be removed by restoring their correct slowly-varying-density limits. It also confirms the relevance of these limits to atoms and molecules.

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