Probing Basis Set Requirements for Calculating Core Ionization and Core Excitation Spectra Using Correlated Wave Function Methods
Probing Basis Set Requirements for Calculating Core Ionization and Core Excitation Spectra Using Correlated Wave Function Methods
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DOI：
10.1021/acs.jctc.1c00042
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发表时间：
2021-04-26
影响因子：
5.5
通讯作者：
Jensen, Frank
中科院分区：
文献类型：
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作者：
Ambroise, Maximilien A.;Dreuw, Andreas;Jensen, Frank
我们调查的基组要求的准确计算的核心激发和核心电离使用相关波函数的耦合集群类型和线性响应方法描述的激励。当芯激发被描述为使用密度泛函理论计算的能量差时，基组可以被定制以提供参考和激发空穴状态的平衡描述。当核心激励过程是由耦合集群线性响应方法描述，但是，基组的要求有些不同。一个系统的研究结果的基组参数的敏感性表明，一个相对较大的一组的s-和p-型基函数结合仔细选择的价和核心极化功能是必需的。在此基础上，我们提出了一个适用于B-Ne原子的分层基组序列，记为ccX-nZ（n = D，T，Q，5），它适用于用关联波函数线性响应和运动方程方法计算核激发.对于给定基数或基函数的数量，ccX-nZ系列提供比其他现有基组更低的基组误差。对于大型系统，可以通过将ccX-nZ仅放置在感兴趣的核心激发的原子上来将ccX-nZ基组与标准基组组合，但是这种混合基组的准确性似乎是系统依赖的。
We investigate the basis set requirements for the accurate calculation of core excitations and core ionizations using correlated wave functions of coupled cluster type and linear response methods for describing the excitation. When a core excitation is described as an energy difference calculated using density functional theory, the basis set can be tailored to provide a balanced description of the reference- and excited-hole states. When the core excitation process is described by coupled cluster linear response methods, however, the basis set requirements are somewhat different. A systematic study of the sensitivity of the result to the basis set parameters suggests that a relatively large set of s- and p-type basis functions in combination with a careful selection of valence and core polarization functions is required. Based on these results, we propose a hierarchical sequence of basis sets, denoted ccX-nZ (n = D, T, Q, 5) for the atoms B-Ne, which are suitable for the calculation of core excitations by the correlated wave function linear response and equation-of-motion methods. The ccX-nZ series provides lower basis set errors for a given cardinal number or number of basis functions than other existing basis sets. For large systems, the ccX-nZ basis sets can be combined with the standard basis sets by placing the ccX-nZ only on the atoms where core excitations are of interest, but the accuracy of such mixed basis sets appears to be system-dependent.