Intermediate Hamiltonian Fock Space Multireference Coupled Cluster Approach to Core Excitation Spectra.
Intermediate Hamiltonian Fock Space Multireference Coupled Cluster Approach to Core Excitation Spectra.
复制标题
核心激发谱的中级哈密顿福克空间多参考耦合聚类方法。
DOI：
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发表时间：
2014
影响因子：
5.5
通讯作者：
S. Pal
中科院分区：
文献类型：
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作者：
A. Dutta;Jitendra Gupta;Nayana Vaval;S. Pal
Fock空间多参考耦合团簇（FSMRCC）方法提供了一种直接计算激发能的有效方法。在中间哈密顿（IH-FSMRCC）制定，该方法是免费的入侵状态问题和相关的收敛困难，即使与一个大的模型空间。本文证明了IH-FSMRCC方法在适当选择模型空间的情况下，可以精确地描述分子的核激发谱，所得结果与实验值符合得很好。我们研究了模型空间的选择对计算结果的影响。与基于运动方程（EOM）的方法不同，IH-FSMRCC不需要任何特殊的收敛技术，并且在单次和双次近似中提供了与标准EOMEE-CCSD方法相当的性能，在某些情况下甚至更好。
The Fock space multireference coupled cluster (FSMRCC) method provides an efficient approach for the direct calculation of excitation energies. In intermediate Hamiltonian (IH-FSMRCC) formulation, the method is free from intruder state problems and associated convergence difficulties, even with a large model space. In this paper, we demonstrate that the IH-FSMRCC method with suitably chosen model space can be used for the accurate description of core excitation spectra of molecules, and our results are in excellent agreement with the experimental values. We have investigated the effect of choice of model space on the computed results. Unlike the equation-of-motion (EOM)-based method, the IH-FSMRCC does not require any special technique for convergence and in singles and doubles approximation gives a performance comparable to that of the standard EOMEE-CCSD method, even better in some of the cases.