论文标题
配置互动校正在配对耦合群集双打的顶部
A configuration interaction correction on top of pair coupled cluster doubles
论文作者
论文摘要
许多数值研究表明，基于Geminal的方法是模拟与计算成本较低的强相关系统的有前途的方向。已经引入了几种策略来捕获缺失的动态相关效应，这些效果通常利用\ textit {a后验}校正来说明与破碎对态或术间相关性相关的相关效应。在本文中，我们仔细检查了对通过配置相互作用（CI）理论扩展的对耦合群集双打（PCCD）方法的准确性。具体而言，我们基准了各种CI模型，包括针对选定的CC校正以及常规的单参考CC方法的最多双重激发。还测试了简单的戴维森校正。评估了提出的PCCD-CI方法的准确性，以挑战小型模型系统，例如\ ce {n2}和\ ce {f2}二聚体以及各种含二氧化二氧化物的二聚体。通常，与常规CCSD方法相比，提出的CI方法可大大改善光谱常数，前提是理论模型中包括戴维森校正。同时，它们的精度位于线性的冷冻PCCD和冷冻PCCD变体之间。
Numerous numerical studies have shown that geminal-based methods are a promising direction to model strongly correlated systems with low computational costs. Several strategies have been introduced to capture the missing dynamical correlation effects, which typically exploit \textit{a posteriori} corrections to account for correlation effects associated with broken-pair states or inter-geminal correlations. In this article, we scrutinize the accuracy of the pair coupled cluster doubles (pCCD) method extended by configuration interaction (CI) theory. Specifically, we benchmark various CI models, including, at most double excitations against selected CC corrections as well as conventional single-reference CC methods. A simple Davidson correction is also tested. The accuracy of the proposed pCCD-CI approaches is assessed for challenging small model systems such as the \ce{N2} and \ce{F2} dimers and various di- and triatomic actinide-containing compounds. In general, the proposed CI methods considerably improve spectroscopic constants compared to the conventional CCSD approach, provided a Davidson correction is included in the theoretical model. At the same time, their accuracy lies between the linearized frozen pCCD and frozen pCCD variants.
