Delocalization error has been singled out by Yang and co-workers as the dominant error in Kohn–Sham density functional theory (KS-DFT) with conventional approximate functionals. In this Letter, by computing the vertical first ionization energy for well separated He clusters, we show that multiconfiguration pair-density functional theory (MC-PDFT) is free from delocalization error. To put MC-PDFT in perspective, we also compare it with some Kohn–Sham density functionals, including both traditional and modern functionals. Whereas large delocalization errors are almost universal in KS-DFT (the only exception being the very recent corrected functionals of Yang and co-workers), delocalization error is removed by MC-PDFT, which bodes well for its future as a step forward from KS-DFT.

中文翻译：

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多配置对密度泛函理论没有离域误差

Yang和他的同事们已经将离域误差选为Kohn-Sham密度泛函理论（KS-DFT）中具有传统近似泛函的主要误差。在这封信中，通过计算良好分离的He团簇的垂直第一电离能，我们证明了多配置对密度泛函理论（MC-PDFT）没有离域误差。为了正确看待MC-PDFT，我们还将其与Kohn-Sham密度函数（包括传统函数和现代函数）进行了比较。尽管较大的离域错误在KS-DFT中几乎是普遍的（唯一的例外是Yang和其同事最近纠正的功能），但MC-PDFT消除了离域错误，这预示着它的未来是从KS向前迈出的一步-DFT。