论文标题
从kohn-sham到多电子能量，通过交换相关电位中的步骤结构
From Kohn-Sham to many-electron energies via step structures in the exchange-correlation potential
论文作者
论文摘要
准确地描述了Kohn-Sham（KS）密度功能理论（DFT）中的激发态，尤其是诱导电离和电荷转移的态，仍然是一个巨大的挑战。对于激发状态，共同的交换相关（XC）近似是由于XC能量中没有导数不连续性（$Δ$）而不可靠的，这将多电子能量差与相应的KS能量差异相关。我们在分析和数值上证明了KS与多电子能量之间的关系如何导致在精确XC电位中观察到的步骤结构，在四种情况下：添加电子，分子解离，有限系统的激发和电荷转移。我们进一步表明，当从集合的角度来解决时，也可以使用常见的XC近似（与LDA一样简单）获得电势中的步骤。因此，本文强调了如何捕获具有高级XC近似值的KS与多电子能量之间的关系对于准确计算激发以及由不同子系统组成的系统的基础密度和能量至关重要。
Accurately describing excited states within Kohn-Sham (KS) density functional theory (DFT), particularly those which induce ionization and charge transfer, remains a great challenge. Common exchange-correlation (xc) approximations are unreliable for excited states owing, in part, to the absence of a derivative discontinuity in the xc energy ($Δ$), which relates a many-electron energy difference to the corresponding KS energy difference. We demonstrate, analytically and numerically, how the relationship between KS and many-electron energies leads to the step structures observed in the exact xc potential, in four scenarios: electron addition, molecular dissociation, excitation of a finite system, and charge transfer. We further show that steps in the potential can be obtained also with common xc approximations, as simple as the LDA, when addressed from the ensemble perspective. The article therefore highlights how capturing the relationship between KS and many-electron energies with advanced xc approximations is crucial for accurately calculating excitations, as well as the ground-state density and energy of systems which consist of distinct subsystems.
