Calculation of the static and dynamical correlation energy of pseudo-one-dimensional beryllium systems via a many-body expansion.
Calculation of the static and dynamical correlation energy of pseudo-one-dimensional beryllium systems via a many-body expansion.
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DOI：
10.1063/1.4955317
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发表时间：
2016-05
期刊：
影响因子：
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通讯作者：
Daniel Koch;E. Fertitta;Beate Paulus
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文献类型：
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作者：
Daniel Koch;E. Fertitta;Beate Paulus
由于静态和动态相关性在键形成中的重要性，低维铍系统构成了有趣的案例研究来测试相关性方法。为了描述扩展Be系统的整个解离曲线，我们选择了应用增量法（MoI）在其多参考（MR）形式主义。为了深入了解波函数的主要特征，我们首先使用标准量子化学方法专注于小Be链的描述。下一步，我们将MoI应用于更大的铍系统，从Be6环开始。采用完整的活性空间形式，并将结果用作整个解离曲线的局部MR计算的参考。虽然这是一个成熟的方法，系统有限的多参考字符，其应用程序的描述整个解离曲线需要进一步测试。在讨论基组的作用之后，该方法最终被应用于更大的环，并外推到无限链。
Due to the importance of both static and dynamical correlation in the bond formation, low-dimensional beryllium systems constitute interesting case studies to test correlation methods. Aiming to describe the whole dissociation curve of extended Be systems we chose to apply the method of increments (MoI) in its multireference (MR) formalism. To gain insight into the main characteristics of the wave function, we started by focusing on the description of small Be chains using standard quantum chemical methods. In a next step we applied the MoI to larger beryllium systems, starting from the Be6 ring. The complete active space formalism was employed and the results were used as reference for local MR calculations of the whole dissociation curve. Although this is a well-established approach for systems with limited multireference character, its application regarding the description of whole dissociation curves requires further testing. Subsequent to the discussion of the role of the basis set, the method was finally applied to larger rings and extrapolated to an infinite chain.