论文标题
精确的两部分TDDFT，具有简单的两电子图片变化：X射线吸收光谱在L-和M-M-Edges附近的四组分质量，以两种成分成本
Exact two-component TDDFT with simple two-electron picture-change corrections: X-ray absorption spectra near L- and M-edges of four-component quality at two-component cost
论文作者
论文摘要
近年来，X射线吸收光谱（XAS）近年来越来越流行，因为它以高空间和元素敏感性很重要。但是，XAS的理论建模是一项具有挑战性的任务，因为XAS光谱具有标量（SC）和自旋轨道（SO）相对论效应，尤其是L和M吸收边缘的精细结构。如今，XAS的完整四组分（4C）计算是可行的，但仍然有兴趣开发近似相对论方法，这些方法可以在两组分（2C）水平上启用XAS计算，同时保持父4C方法的准确性。 In this article we present theoretical and numerical insights into two simple yet accurate 2c approaches based on an (extended) atomic mean-field exact two-component Hamiltonian framework, (e)amfX2C, for the calculation of XAS using linear eigenvalue and damped-response time-dependent density functional theory (TDDFT).与常用的单电子X2C（1EX2C）Hamiltonian相比，AMFX2C和EAMFX2C都对SC进行了解释，因此由X2C转换产生的两电子和交换相关图片变化（PC）效应。 As we demonstrate on L- and M-edge XAS spectra of transition metal and actinide compounds, the absence of PC corrections in the 1eX2C approximation results in a substantial overestimatation of SO splittings, whereas (e)amfX2C Hamiltonians reproduce all essential spectral features such as shape, position, and SO splitting of the 4c references in excellent agreement, while offering significant computational savings.因此，此处介绍的（E）AMFX2C PC校正模型构成了用于建模XAS的可靠相对论2C量子化学方法。
X-ray absorption spectroscopy (XAS) has gained popularity in recent years as it probes matter with high spatial and elemental sensitivity. However, the theoretical modelling of XAS is a challenging task since XAS spectra feature a fine structure due to scalar (SC) and spin-orbit (SO) relativistic effects, in particular near L and M absorption edges. While full four-component (4c) calculations of XAS are nowadays feasible, there is still interest in developing approximate relativistic methods that enable XAS calculations at the two-component (2c) level while maintaining the accuracy of the parent 4c approach. In this article we present theoretical and numerical insights into two simple yet accurate 2c approaches based on an (extended) atomic mean-field exact two-component Hamiltonian framework, (e)amfX2C, for the calculation of XAS using linear eigenvalue and damped-response time-dependent density functional theory (TDDFT). In contrast to the commonly used one-electron X2C (1eX2C) Hamiltonian, both amfX2C and eamfX2C account for the SC and SO two-electron and exchange-correlation picture-change (PC) effects that arise from the X2C transformation. As we demonstrate on L- and M-edge XAS spectra of transition metal and actinide compounds, the absence of PC corrections in the 1eX2C approximation results in a substantial overestimatation of SO splittings, whereas (e)amfX2C Hamiltonians reproduce all essential spectral features such as shape, position, and SO splitting of the 4c references in excellent agreement, while offering significant computational savings. Therefore, the (e)amfX2C PC correction models presented here constitute reliable relativistic 2c quantum-chemical approaches for modelling XAS.
