论文标题
从优化孔的线性响应颗粒中计算X射线吸收光谱
Computing X-ray absorption spectra from linear-response particles atop optimized holes
论文作者
论文摘要
状态特异性轨道优化的密度功能理论（OO-DFT）方法（例如受限的开放式Kohn-Sham（ROKS））可以获得半定量精度，以预测封闭壳分子的X射线吸收光谱。但是，OO-DFT方法需要单独优化每个状态。在这项工作中，我们提出了一种方法，可以生成与Roks Energy Ansatz一起使用的近似核心兴奋的状态密度，该状态可以提供合理的精度而无需特定于州的优化。这是通过通过核心离子状态充分优化核心孔的，然后使用电子添加构型相互作用单打（EA-CIS）来获得粒子水平。这种混合方法可以看作是静态交换方法（STEX）方法的DFT概括，并且可以通过使用PBE和OLYP（例如PBE和OLYP）来实现C-F的K-EDGE的$ \ sim 0.6 $ EV RMS错误。这种ROKS（STEX）方法也可用于确定全面OO ROKS治疗的重要过渡，因此可以帮助降低获得OO-DFT质量光谱的计算成本。因此，ROKS（STEX）似乎是有效预测X射线吸收光谱的有用技术。
State specific orbital optimized density functional theory (OO-DFT) methods like restricted open-shell Kohn-Sham (ROKS) can attain semiquantitative accuracy for predicting X-ray absorption spectra of closed-shell molecules. OO-DFT methods however require that each state be individually optimized. In this work, we present an approach to generate an approximate core-excited state density for use with the ROKS energy ansatz, that is capable of giving reasonable accuracy without requiring state-specific optimization. This is achieved by fully optimizing the core-hole through the core-ionized state, followed by use of electron-addition configuration interaction singles (EA-CIS) to obtain the particle level. This hybrid approach can be viewed as a DFT generalization of the static-exchange (STEX) method, and can attain $\sim 0.6$ eV RMS error for the K-edges of C-F through the use of local functionals like PBE and OLYP. This ROKS(STEX) approach can also be used to identify important transitions for full OO ROKS treatment, and can thus help reduce the computational cost for obtaining OO-DFT quality spectra. ROKS(STEX) therefore appears to be a useful technique for efficient prediction of X-ray absorption spectra.
