(Semi)-local density functional approximations (DFAs) suffer from self-interaction error (SIE). When the first ionization energy (IE) is computed as the negative of the highest-occupied orbital (HO) eigenvalue, DFAs notoriously underestimate them compared to quasi-particle calculations. The inaccuracy for the HO is attributed to SIE inherent in DFAs. We assessed the IE based on Perdew–Zunger self-interaction correction on 14 small to moderate-sized organic molecules relevant in organic electronics and polymer donor materials. Although self-interaction corrected DFAs were found to significantly improve the IE relative to the uncorrected DFAs, they overestimate. However, when the self-interaction correction is interiorly scaled using a function of the iso-orbital indicator z_σ, only the regions where SIE is significant get a correction. We discuss these approaches and show how these methods significantly improve the description of the HO eigenvalue for the organic molecules.

中文翻译：

---

Fermi–Löwdin自相互作用校正，用于有机分子的电离能

（半）局部密度泛函近似（DFA）遭受自相互作用误差（SIE）。当将第一电离能（IE）计算为最大占据轨道（HO）特征值的负值时，与准粒子计算相比，DFA显然低估了它们。HO的不准确性归因于DFA中固有的SIE。我们基于Perdew-Zunger自相互作用校正对14种与有机电子和聚合物供体材料相关的小至中型有机分子的IE进行了评估。尽管发现自交互校正的DFA相对于未校正的DFA显着改善了IE，但它们却高估了。然而，当自相互作用校正是使用异轨道指示符的函数在内部缩放ž _σ，只有SIE显着的区域才会得到校正。我们讨论这些方法，并展示这些方法如何显着改善有机分子HO特征值的描述。