Energy-Specific Equation-of-Motion Coupled-Cluster Methods for High-Energy Excited States: Application to K-edge X-ray Absorption Spectroscopy.
Energy-Specific Equation-of-Motion Coupled-Cluster Methods for High-Energy Excited States: Application to K-edge X-ray Absorption Spectroscopy.
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DOI：
10.1021/acs.jctc.5b00459
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发表时间：
2015-08
影响因子：
5.5
通讯作者：
B. Peng;Patrick J. Lestrange;J. Goings;M. Caricato;Xiaosong Li
中科院分区：
文献类型：
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作者：
B. Peng;Patrick J. Lestrange;J. Goings;M. Caricato;Xiaosong Li
基于耦合团簇（CC）理论的单参考技术，以线性响应（LR）或运动方程（EOM）的形式，是用于建模价吸收光谱的高度精确且广泛使用的方法。不幸的是，这些方程与单和双（LR-CCSD和EOM-CCSD）的规模为O（N），这可能是昂贵的高能量激发态的研究使用传统的本征解算器。在本文中，我们提出了一个能量特定的非厄米特本征解，能够获得高能量激发态（例如，XAS K边缘谱）。此外，我们还介绍了一种改进的试探向量迭代求解EOM-CCSD方程的重点是高能量本征态。能量特定的EOM-CCSD方法及其低尺度的替代品被应用到碳，氮，氧和硫的K边激发的计算。结果进行比较，CCSD的激发态，能量特定的线性响应依赖于时间的密度泛函理论（TDDFT）的其他实现，并与多个统计指标的实验结果进行了介绍和评估。
Single-reference techniques based on coupled-cluster (CC) theory, in the forms of linear response (LR) or equation of motion (EOM), are highly accurate and widely used approaches for modeling valence absorption spectra. Unfortunately, these equations with singles and doubles (LR-CCSD and EOM-CCSD) scale as O(N⁶), which may be prohibitively expensive for the study of high-energy excited states using a conventional eigensolver. In this paper, we present an energy-specific non-Hermitian eigensolver that is able to obtain high-energy excited states (e.g., XAS K-edge spectrum) at low computational cost. In addition, we also introduce an improved trial vector for iteratively solving the EOM-CCSD equation with a focus on high-energy eigenstates. The energy-specific EOM-CCSD approach and its low-scaling alternatives are applied to calculations of carbon, nitrogen, oxygen, and sulfur K-edge excitations. The results are compared to other implementations of CCSD for excited states, energy-specific linear response time-dependent density functional theory (TDDFT), and experimental results with multiple statistical metrics are presented and evaluated.