J Chem Theory Comput. 2023 Feb 14;19(3):799-807. doi: 10.1021/acs.jctc.2c00899. Epub 2023 Jan 24.
A formally exact density functional theory (DFT) determination of the average electron energy is presented. Our theory, which is based on a different accounting of energy functional terms, partially solves one well-known downside of conventional Kohn-Sham (KS) DFT: that electronic energies have but tenuous connections to physical quantities. Calculated average electron energies are close to experimental ionization potentials (IPs) in one-electron systems, demonstrating a surprisingly small effect of self-interaction and other exchange-correlation errors in established DFT methods. Remarkable agreement with ab initio quantum mechanical calculations of multielectron systems is demonstrated using several flavors of DFT, and we argue for the use of the average electron energy as a design criterion for density functional approximations.
本文提出了一种精确的平均电子能量的密度泛函理论（DFT）确定方法。我们的理论基于对能量泛函项的不同解释，部分解决了传统 Kohn-Sham（KS）DFT 的一个众所周知的缺点：电子能量与物理量的联系很微弱。在单电子体系中，计算得到的平均电子能量与实验电离能（IPs）非常接近，这表明在已建立的 DFT 方法中，自相互作用和其他交换相关误差的影响很小。使用几种 DFT 方法，我们展示了与多电子体系的从头算量子力学计算的惊人一致，并主张将平均电子能量用作密度泛函近似的设计标准。
